Safety Relief Valves

SafetyReliefValves

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Registered Office: Sharp Street,Worsley,Manchester M28 3NA, UK.

P l e a s e c o m p l e t e t h e f o l l ow i n g

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Safety Systems UK LtdSharp Street,Worsley Manchester, UKM28 3NATel +44 (0)161 790 7741Fax +44 (0)161 703 8451Email [email protected] site: www.safetysystemsuk.com

Simply photocopy andfax to us for moreinformation on. . .

P l e a s e t i c k b o xw h e r e a p p r o p r i a t e

F a x b a c k t o u s o n

Fax: +44 (0)161 703 8451

Associated Products

Standard Safety Relief Valves

700 Series Safety Relief Valves

Direct Acting Pressure Reducing Valves

Marvac Pressure/Vacuum Valves

Marston Bursting Discs & Explosion Vent Panels

Amal Flame Arresters

G4 Pilot Operated Pressure Reducing Valves

L O C A L D I S T R I B U TO R

Assistance:

Our experienced and fully trained team of Technical Sales Engineers

and distributors are available to give advice and assistance on the

sizing and selection of the Birkett range and any other associated

products.

This service is available to you by calling your local distributor or

our Birkett Technical Sales Department, who will be happy to help.

Details of our worldwide network of distributors and regional

offices are available on our website.

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S E C T I O N PAG E C O N T E N T S

Birkett Range 3 Valve type descriptions

4 International approvals and authorisations

WB Series 5 - 6 Design features and benefits

7 - 10 Valve types and action

11 - 14 Drawings

15 - 16 Accessories

17 Figure numbering system

18 Material temperature ranges

19 - 46 Valve selection charts, D to T

47 - 48 Valve adjustment

49 - 50 Seat tightness/seat leakage testing

Safeflo 51 Design features


53 - 54 Drawings

55 Accessories

56 Dimensions

Safeset 57 - 59 Design features and benefits

59 Dual Outlet/Full Bore Pilot Valve

60 Pilot types and basic operation

61 - 62 Type A - Pop Action Pilot

63 - 66 Type B and D - Modulating Action Pilot

67 - 69 Type C and E - Pop/Modulating Action Pilot

70 Liquid and dual phase piping arrangement

71 Technical specification

71 - 72 Drawings and materials of construction

73 - 75 Accessories


77 - 78 Dimensions

79 - 80 Operating pressure/temperature limits

Sizing 81 - 82 Sizing formula

83 Nomenclature

84 Back pressure/blowdown limits and orifice areas

85 - 90 Sizing factors

91 - 96 Capacity charts

97 Reaction forces

Definitions 98 Definitions of terms

99 Operational characteristics

100 Pressure term relationships

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The effects of exceeding safe pressure levels inan unprotected pressure vessel or system, canhave catastrophic effects on both plant andpersonnel.

Safety relief valves should be used to protectany pressurised system from the effects ofexceeding its design pressure limit.

A safety relief valve is designed to automaticallydischarge gas, vapour or liquid from anypressure containing system, preventing apredetermined safe pressure being exceeded,and protecting plant and personnel.

Introduction

The Birkett range of safety relief valvescontains three distinct valve types:

WB Series – spring loaded safety relief valves.Safeflo – safety and thermal relief valves.Safeset – pilot operated safety relief valves.

All types are certified in accordance with ASME Code Section VIII.

All Birkett valves are available

through our global

agent distribution network,

supported by our own

regional sales offices

around the world.

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APPLICABLE STANDARDS

ISO 9001 Quality Standard

ASME Code Section VIII All valves are UV certified

API 520 : Part 1 Sizing and selection

API 526 Dimensions

API 527 Leakage Rates

ANSI B16.5Flange Ratings

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I N T E R N AT I O N A L A P P R OVA L S A N D A U T H O R I S AT I O N S

Our approvals and accreditationsinclude ISO 9001, ASME, UDT, ChineseSafety Quality Licence,TUV, DNV,Bureau Veritas and Stoomwezen.

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‘WB’ Series spring loaded safety relief valve

The WB is designed to safely relieve excess pressurein pumps, pipework, tanks, calorifiers, gas and oilseparators and other process vessels. It is suitablefor gas, steam, vapour and liquid applications. TheWB conforms to API 526 pressure/temperatureranges, orifice areas and dimensions.

‘Safeflo’ safety and thermal relief valves

Safeflo valves are designed for similar dutiesto the WB but for small capacity applications.They safely relieve thermal expansion ofprocess fluids in vessels and long lengths ofpipework, and are suitable for gas and liquidapplications.

‘Safeset’ pilot operated safety relief valve

Safeset valves are self contained pilot operated safetyrelief valves which use the system pressure to controlthe valve opening and closing. No other source ofenergy is required.A choice of different types of Safeset pilot valves areavailable, including pop and modulating action to suit avariety of applications.

Safeset valves conform to API 526 pilot operatedpressure/temperature ranges and dimensions, withmultiple orifice areas contained within each valvebody size.

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T H E B I R K E T T R A N G E

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Design verification – all design options and thevarious effects of system conditions, back pressureetc. have been verified on Birkett’sin-house, extensive mass flow test facility.

Lighter and more compact construction –continuous design improvements have createdsmaller and lighter valves to support currentindustry design trends, especially space and weightsavings.

Interchangeable parts – valves can be modifiedfrom type to type, gas, liquid, conventional andbellows simply by changing only a few parts.

Simplified maintenance and service -re-engineering has reduced the number of parts,making maintenance easier and more cost effective.

Material selection – a wide range of materialsare offered including non-ferrous for lowtemperature and oxygen service, as well as exoticalloys specifically for the chemical and processindustries.

Cryogenic and oxygen service – Birkett’s state-of-the-art clean room and vapour degreasingfacilities ensure compliance with the stringentdemands of cryogenic and oxygen applications.

F E AT U R E S A N D B E N E F I T S

1 In-situ testing – valves are supplied suitablefor application of “in-situ” set pressureverification devices.

2 Wide range of accessories – available tocomply with international codes and to suitsystem requirements.

3 High performance springs – safety reliefvalve springs are specifically designed toguarantee set point repeatability.

4 Bellows back-up piston – an optionalauxiliary back-up piston for balanced bellowsvalves ensures fail-safe operation in the eventof bellows failure (see page 16).

5 Guiding surfaces – the material selection ofguiding components, together with a self-aligning disc and spindle pivot point, ensurescorrect alignment and no galling of guidingsurfaces.

6 Bellows – ensures correct valve performanceunder difficult back pressure conditions (seepage 12).

7 Trim – specific gas and liquid trim designsgive stable operation and eliminate thedamaging effect of chatter.

8 Seat leakage integrity – choice of nozzleand disc materials (coupled with superiorlapping techniques) provides seat tightness toa higher standard than that required byrelevant codes.

9 Adjustable blow down – the valvereseating pressure (blow down) can be simplyadjusted to suit special or specificperformance requirements.

10 Nozzle design – the method and location ofattachment to the body avoids transmissionof pipe stresses to the nozzle/disc matingsurfaces.

11 API 526 dimensions – standardiseddimensions allows pipework layouts to bedetailed confidently.

WB Series

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D E S I G N F E AT U R E S

WB Series - Spring Loaded Safety Relief Valve

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1 Insitu testing

2 Accessories

3 High performance springs

4 Bellows back up piston(not shown)

6 Bellows(not shown)

7 Trim

8 Seat integrity

9 Adjustable blow down

10 Nozzle design

11 API 526 face to facedimensions

5 Guiding

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T H E E F F E C T O F B AC K P R E S S U R E

The configuration of a closed discharge pipeworksystem, typically for toxic or hazardous duty, cangenerate back pressure. Back pressure applied tothe outlet of the valve will adversely affect itsperformance, unless it is addressed.

Back pressure may take three forms:

1. Superimposed constant back pressure

This exists permanently and a conventional orbellows valve can be used. A conventional valvecan be set at the differential pressure so that thespring load is adjusted to take account of the backpressure.

2. Built up back pressure

Built up back pressure is created by theconfiguration of discharge pipework systems andvaries from zero when the valve is closed, to amaximum, when fully open. Conventional springloaded valves can tolerate up to 10% of setpressure as built up back pressure. For backpressures in excess of 10%, a balanced bellowsdesign is required to maintain valve lift.

Constant back pressure - conventional valve

SPRING LOAD (DIFFERENTIAL PRESSURE)150lbf/in2

INLET PRESSURE200lbf/in2

INLET PRESSURE = SPRING LOAD + BACK PRESSUREOR

DIFFERENTIAL PRESSURE = INLET PRESSURE - BACK PRESSURE

CONSTANTBACK PRESSURE

50lbf/in2

Variable back pressure - balanced bellows valve

SPRING LOAD (SET PRESSURE)200lbf/in2


INLET PRESSURE TO LIFT VALVE= SPRING LOAD SET PRESSURE

BACK PRESSURE0 - 50lbf/in2

3. Superimposed variable back pressure

This is caused by other valves discharging into acommon disposal system, or other circumstancesthat cause the back pressure to be variable.Balanced bellows valves should be used for thiscondition, adjusted to the predetermined setpressure.

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D I F F E R E N T T Y P E S

Liquid Service

Valves operating on liquid service require amodified valve design to cope with the differingdynamics of liquid flow.

A contoured plug disc is used to minimise initialflow rate, eliminating any potential inlet pressuredrops due to excessive valve lift. The valve willsimmer until sufficient pressure is available togenerate lift. Once this has occurred, the lift willstabilise to suit the flow and pressure conditionsrequired, thus avoiding the problem of chatter.

‘Chatter’ is the rapid opening and closing of thevalve which can have a damaging effect on the discand nozzle, causing it to leak.

Typical liquid relief valve disc

There are four basic types of WB Series safetyrelief valve:

WB400 – conventional gas type.

WB300 – bellows gas type.

WB200 – conventional liquid type.

WB100 – bellows liquid type.

Conventional safety relief valves:Can be used on systems where the discharge isrelatively simple.The pressure in the dischargesystem can be atmospheric, at a constant level orwhere the pressure may build up to a maximum of10% of the set pressure. When a constant backpressure exists, the valve should be set at thedifferential pressure (refer to page 8).

Bellows safety relief valves:The WB Bellows Valves are statically balanced andcan be used on more complex discharge systemssuch as common discharge manifolds and flareswhere several valves may discharge.This type ofsystem creates a variable superimposed backpressure.The balanced bellows unit cancels out theeffects of variable back pressure, on the setpressure of the safety relief valve.

Gas and vapour service:The gas/vapour disc can be distinguished by the flatunderside, unlike the cone profile of the liquid disc.

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T H E E F F E C T O F B AC K P R E S S U R E

The configuration of a closed discharge pipeworksystem, typically for toxic or hazardous duty, cangenerate back pressure. Back pressure applied tothe outlet of the valve will adversely affect itsperformance, unless it is addressed.

Back pressure may take three forms:

1. Superimposed constant back pressure

This exists permanently and a conventional orbellows valve can be used. A conventional valvecan be set at the differential pressure so that thespring load is adjusted to take account of the backpressure.

2. Built up back pressure

Built up back pressure is created by theconfiguration of discharge pipework systems andvaries from zero when the valve is closed, to amaximum, when fully open. Conventional springloaded valves can tolerate up to 10% of setpressure as built up back pressure. For backpressures in excess of 10%, a balanced bellowsdesign is required to maintain valve lift.

Constant back pressure - conventional valve

SPRING LOAD (DIFFERENTIAL PRESSURE)150lbf/in2


INLET PRESSURE = SPRING LOAD + BACK PRESSUREOR

DIFFERENTIAL PRESSURE = INLET PRESSURE - BACK PRESSURE

CONSTANTBACK PRESSURE

50lbf/in2

Variable back pressure - balanced bellows valve

SPRING LOAD (SET PRESSURE)200lbf/in2


INLET PRESSURE TO LIFT VALVE= SPRING LOAD SET PRESSURE

BACK PRESSURE0 - 50lbf/in2

3. Superimposed variable back pressure

This is caused by other valves discharging into acommon disposal system, or other circumstancesthat cause the back pressure to be variable.Balanced bellows valves should be used for thiscondition, adjusted to the predetermined setpressure.

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D I F F E R E N T T Y P E S

Liquid Service

Valves operating on liquid service require amodified valve design to cope with the differingdynamics of liquid flow.

A contoured plug disc is used to minimise initialflow rate, eliminating any potential inlet pressuredrops due to excessive valve lift. The valve willsimmer until sufficient pressure is available togenerate lift. Once this has occurred, the lift willstabilise to suit the flow and pressure conditionsrequired, thus avoiding the problem of chatter.

‘Chatter’ is the rapid opening and closing of thevalve which can have a damaging effect on the discand nozzle, causing it to leak.

Typical liquid relief valve disc

There are four basic types of WB Series safetyrelief valve:

WB400 – conventional gas type.

WB300 – bellows gas type.

WB200 – conventional liquid type.

WB100 – bellows liquid type.

Conventional safety relief valves:Can be used on systems where the discharge isrelatively simple.The pressure in the dischargesystem can be atmospheric, at a constant level orwhere the pressure may build up to a maximum of10% of the set pressure. When a constant backpressure exists, the valve should be set at thedifferential pressure (refer to page 8).

Bellows safety relief valves:The WB Bellows Valves are statically balanced andcan be used on more complex discharge systemssuch as common discharge manifolds and flareswhere several valves may discharge.This type ofsystem creates a variable superimposed backpressure.The balanced bellows unit cancels out theeffects of variable back pressure, on the setpressure of the safety relief valve.

Gas and vapour service:The gas/vapour disc can be distinguished by the flatunderside, unlike the cone profile of the liquid disc.

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Stage 1 – Closed

Inlet pressure < set pressureInlet pressure is below the set pressure. The valve isclosed and there is no flow through the valve.

HUDDLINGCHAMBER

REACTIONHOOD

EXITAREA

BLOWDOWNRING

INLET

Stage 2 – Simmering

Inlet pressure is = > set pressure and < popping pressure

Inlet pressure increases to set pressure. At this point, the springforce and system pressure force are equal; a further rise in inletpressure will then begin to lift the disc slightly. A small amount offluid is released into the huddling chamber (the valve simmers).The system fluid is now acting on a larger area inside thehuddling chamber.

Stage 3 – Popping and Opening

Inlet pressure = > popping pressure, valve fully open

The inlet pressure acting on a larger area produces a significantforce to accelerate the opening. A combination of this pressureforce, the kinetic energy from the fluid within the nozzle and thedeflection force of the fluid flow turning through the reactionhood, is transformed into disc lifting force. The valve pops openat < 5% overpressure and the valve reaches the full openposition at 110% of set pressure, in accordance withinternational codes.

Stage 4 – Reseating

Inlet pressure falls to re-seating pressure

As system pressure starts to fall, the force from the springbegins to close the valve. Typically, the system pressure fallsbetween 5-10% below the valve set pressure at which point thespring force accelerates the valve disc to re-seat the valve.Thedifference between the set pressure and the re-seating pressureis known as blowdown.

L I F T C Y C L E

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SPRING FORCE

SYSTEM PRESSURE FORCE

Principles of operation – spring loadedsafety and thermal relief valves

Safety relief valves use a spring force to hold a discagainst a nozzle. Under normal system operatingpressure, the valve will remain closed as the springforce is greater than the inlet system pressureforce. The valve opens when the system pressureforce becomes greater than the closing force of thespring.

Spring loaded safety and thermal relief valve

The WB and B/C series are designed to have ashort simmer, open rapidly to full lift position andthen re-seat at a controlled shut off pressure.

This is demonstrated in the graph below, whichshows the valve action and corresponding pressureat the valve inlet.

POPPING PRESSURE

RE-SEAT PRESSURE

Blowdown

Overpressure

SIMMER

STAGE 1 STAGE 2 STAGE 3 STAGE 4

Popping PointSet Point Full Lift Position Re-seat Point

PRESSURE

SET PRESSURE

LIFT

Popping and blowdown

The opening and closing characteristics of the valvecan be controlled by the adjustment of ablowdown ring, as its position affects the shape andvolume of the huddling chamber. When theblowdown ring is adjusted to its top position, theexit area from the huddling chamber is restrictedto its minimum.The valve will pop distinctly with ashort simmer and long blowdown. Conversely,

when the blowdown ring is in its lowest positionthere is a maximum exit area from the huddlingchamber and the valve will have a longer simmerwith a shorter blowdown. The blowdown ring canbe positioned between these two extremes to givethe required performance, but it is usually factoryset to achieve re-seating 7-10% below set pressure.

VA LV E AC T I O N

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(up to and including class 600)

W B 3 0 0 - B A L A N C E D B E L L OW S G A S T Y P E

ITEM PART CARBON STEEL STAINLESS STEEL

1 Body SA 216-WCB CARB ST SA 351-CF8M ST ST2 Casing SA 216-WCB CARB ST SA 351-CF8M ST ST3 Cap SA 216-WCB CARB ST SA 351-CF8M ST ST4* Nozzle ASTM A479-316L ASTM A479-316L5* Disc ASTM A479-316L ASTM A479-316L6* Disc holder INCLUDED IN ITEM 23 INCLUDED IN ITEM 238 Blowdown ring SA 351-CF8 ST ST SA 351-CF8 ST ST9 Guide Assy CARBON ST/17-4 ST ST 316 L/17-4 ST ST10* Spindle ASTM A479-431 ASTM A479-43111 Lower spring plate ASTM A108-1021/Ni PLT ASTM A479-43112 Adjusting screw ASTM A479-410 ASTM A479-41013 Locking nut ASTM A108-1021 ASTM A479-316L14 Setting screw ASTM A479-431 ASTM A479-43115 Set screw rod ASTM A479-316L ASTM A479-316L18 Stud SA 193-B7 CR/MOL ST SA 193-B8T ST ST19 Nut SA 194-2H CARB ST SA 194-8T ST ST22* Spring CARBON STEEL ASTM A313-31623* Bellows assembly ASTM A479-316L/SA240-316L ASTM A479-316L/SA240-316L27* Body gasket ST-706 ST-70628* Cap gasket ST-706 ST-70629* Set screw gasket ST-706 ST-70631* Ball AISI 440C ST ST AISI 440C ST ST32 Upper spring plate ASTM A108-1021/Ni PLT ASTM A479 43133 Data plate 321 ST ST 321 ST ST34 Hammer drive screw ELECTRO BRASSED ST ASTM A479-316L35 Grooved pin ASTM A479-431 ASTM A479-43142 Drain plug HTS HOLO-KROME ASTM A479-316L80* Circlip ASTM A313-316 ASTM A313-316

* Recommended spares

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23

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31

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80

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15

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27

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12

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14

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9

31

5

80

6

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15

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12

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19

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(up to and including class 600)

W B 4 0 0 - C O N V E N T I O N A L G A S T Y P E


1 Body SA 216-WCB CARB ST SA 351-CF8M ST ST2 Casing SA 216-WCB CARB ST SA 351-CF8M ST ST3 Cap SA 216-WCB CARB ST SA 351-CF8M ST ST4* Nozzle ASTM A479-316L ASTM A479-316L5* Disc ASTM A479-316L ASTM A479-316L6* Disc holder ASTM A479-316L ASTM A479-316L8 Blowdown ring SA 351-CF8 ST ST SA 351-CF8 ST ST9 Guide Assy CARBON ST/17-4 ST ST 316L/17-4 ST ST10* Spindle ASTM A479-431 ASTM A479-43111 Lower spring plate ASTM A108-1021/Ni PLT ASTM A479-43112 Adjusting screw ASTM A479-410 ASTM A479-41013 Locking nut ASTM A108-1021 ASTM A479-316L14 Setting screw ASTM A479-431 ASTM A479-43115 Setting screw rod ASTM A479-316L ASTM A479-316L18 Stud SA 193-B7 CR/MOL ST SA 193-B8T ST ST19 Nut SA 194-2H CARB ST SA 194-8T ST ST22* Spring CARBON STEEL ASTM A313-31627* Body gasket ST-706 ST-70628* Cap gasket ST-706 ST-70629* Set screw gasket ST-706 ST-70631* Ball AISI 440C ST ST AISI 440C ST ST32 Upper spring plate ASTM A108-1021/Ni PLT ASTM A479-43133 Data plate 321 ST ST 321 ST ST34 Hammer drive screw ELECTRO BRASSED ST ASTM A479-316L35 Grooved pin ASTM A479-431 ASTM A479-43142 Drain plug HTS HOLO-KROME ASTM A479-316L80* Circlip ASTM A313-316 ASTM A313-316


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(class 900 and above)

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18

14

42

29

19

23

25

9

31

6

7

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1

4

15

3

2

33

34

27

35

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22

12

13

28

11

24

10

265

17

16

21

20

36

50

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1 Body SA 216-WCB CARB ST SA 351-CF8M ST ST2 Casing SA 216-WCB CARB ST SA 351-CF8M ST ST3 Cap SA 216-WCB CARB ST SA 351-CF8M ST ST4* Nozzle ASTM A479-316L ASTM A479-316L5* Disc ASTM A479-316L ASTM A479-316L6* Disc holder base ASTM A479-321 ASTM A479-3217 Reaction hood ASTM A479-431 ASTM A479-4318 Blowdown ring AMS 5360 AMS 53609 Guide plate 17-4 ST ST 17-4 ST ST10* Spindle ASTM A479-431 ASTM A479-43111 Lower spring cap ASTM A108-1021/Ni PLT ASTM A479-43112 Adjusting screw ASTM A479-410 ASTM A479-41013 Locking nut ASTM A108-1021 ASTM A479-316L14 Setting screw ASTM A479-431 ASTM A479-43115 Setting screw rod ASTM A479-316L ASTM A479-316L16* Tabwasher BS 1449-304S15 ST ST BS 1449-304S15 ST ST17* Pinning screw ASTM A479-431 ASTM A479-43118 Body stud SA 193-B7 CR/MOL ST SA 193-B8T ST ST19 Body nut SA 194-2H CARB ST SA 194-8T ST ST20 Casing stud SA 193-B7 CR/MOL ST SA 193-B8T ST ST21 Casing nut SA 194-2H CARB ST SA 194-8T ST ST22* Spring CARBON STEEL ASTM A313-31623* Bellows SA240-316L SA240-316L24* Spindle head ASTM A479-431 ASTM A479-43125 Piston ASTM A479-431 ASTM A479-43126 Guide spindle ASTM A479-321 ASTM A479-343127* Body gasket ST-706 ST-70628 Cap gasket ST-706 ST-70629 Setting screw gasket ST-706 ST-70631 Ball AISI 440C ST ST AISI 440C ST ST32 Upper spring cap ASTM A108-1021/Ni PLT ASTM A479 43133 Data plate 321 ST ST 321 ST ST34 Hammer drive screw ELECTRO BRASSED ST ASTM A479-316L35 Grooved pin ASTM A479-431 ASTM A479-43136 Eye bolt HTS HOLO-KROME HTS HOLO-KROME42 Drain plug HTS HOLO-KROME ASTM A479-316L50 Grubscrew ASTM A479-321 ASTM A479-321

* Recommended spares13

(class 900 and above)

W B 4 0 0 - C O N V E N T I O N A L G A S T Y P E

18

14

42

29

19

9

6

31

5

7

8

1

4

15

3

2

33

34

27

35

32

22

12

13

28

11

24

17

16

10

21

20

36

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1 Body SA 216-WCB CARB ST SA 351-CF8M ST ST2 Casing SA 216-WCB CARB ST SA 351-CF8M ST ST3 Cap SA 216-WCB CARB ST SA 351-CF8M ST ST4* Nozzle ASTM A479-316L ASTM A479-316L5* Disc ASTM A479-316L ASTM A479-316L6* Disc holder ASTM A479-316L ASTM A479-316L7 Reaction hood ASTM A479-431 ASTM A479-4318 Blowdown ring SA 351-CF8 ST ST SA 351-CF8 ST ST9 Guide plate 17-4 ST ST 17-4 ST ST10* Spindle ASTM A479-431 ASTM A479-43111 Lower spring cap ASTM A108-1021/Ni PLT ASTM A479-43112 Adjusting screw ASTM A479-410 ASTM A479-41013 Locking nut ASTM A108-1021 ASTM A479-316L14 Setting screw ASTM A479-431 ASTM A479-43115 Setting screw rod ASTM A479-316L ASTM A479-316L16* Tabwasher BS 1449-304S15 ST ST BS 1449-304S15 ST ST17* Pinning screw ASTM A479-431 ASTM A479-43118 Body stud SA 193-B7 CR/MOL ST SA 193-B8T ST ST19 Body nut SA 194-2H CARB ST SA 194-8T ST ST20 Casing stud SA 193-B7 CR/MOL ST SA 193-B8T ST ST21 Casing nut SA 194-2H CARB ST SA 194-8T ST ST22* Spring CARBON STEEL ASTM A313-31624* Spindle head ASTM A479-431 ASTM A479-43127* Body gasket ST-706 ST-70628* Cap gasket ST-706 ST-70629* Setting screw gasket ST-706 ST-70631* Ball AISI 440C ST ST AISI 440C ST ST32 Upper spring cap ASTM A108-1021/Ni PLT ASTM A479 43133 Data plate 321 ST ST 321 ST ST34 Hammer drive screw ELECTRO BRASSED ST ASTM A479-316L35* Grooved pin ASTM A479-431 ASTM A479-43136 Eye bolt HTS HOLO-KROME HTS HOLO-KROME42 Drain plug HTS HOLO-KROME ASTM A479-316L


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Ferrule (government ring)

A ferrule, sometimes known as a government ring,is a collar fitted beneath the head of the pressureadjusting screw. Some authorities will require aferrule to be fitted to prevent unauthorised inter-ference with the set pressure.

Steam jacket

Some process media can solidify orform crystals if they cool withinthe system.The medium withinthe valve nozzle is not in theflow path and thus cooling canoccur. Should the mediumsolidify, crystallise, or ifsublimation of vapourwas to occur withinthe nozzle, the valvemay not lift.

The steam jacket isdesigned to keep the processmedium hot, helping tomaximise plant safety.The steam jacket has both aninlet and outlet so that low pressure steam can bepassed through the jacket, keeping the valves hot.This allows the valves to stay operational, enablingthe valve to successfully relieve pressure, should anoverpressure situation occur.

The steam jacket is manufactured out of materialthat is compatible with the body of the valve andthe connections to the jacket can either be flangedor screwed.

FERRULE

Soft seat

An O-ring seal offers maximum seat tightness, overand above that of the standard metal-to-metalseats. A wide range of seal materials are availableincluding Viton, Nitrile, Kalrez and PTFE. For highintegrity seat leakage, specify soft seat.

Auxiliary back-up piston

In the event of bellows failure, a potentiallydangerous situation can arise.The back pressurecauses an “out-of-balance” situation which maycause:

1 Increase in set pressure.2 Decrease in flow capacity.3 Increase in re-seat pressure.

Specifying bellows valves with an auxiliary back-uppiston ensures that the above does not occur.Thepiston itself has the same effective diameter as thefailed bellows, so any effect of the back pressureincreasing the set pressure is counteracted by anupward thrust of the piston. This is an added safetyfeature. The WB 300 valve has incorporated theauxiliary back-up piston since its inception. It isavailable as standard in all pressure classes 900 andabove and as an optional feature for class 600 andbelow.

To ensure absolute safety, specify the auxiliaryback-up piston.

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AC C E S S O R I E S

Bolted cap

Option available on the WB Series when requiredby the customer or for critical service wherefragile gaskets materials may be fitted.

Screwed cap

This is the standard option on all valves.

Open lever*

The open lever assembly is not pressure tight andis therefore only suitable where vapour can safelybe allowed to escape to atmosphere. Packed lever*

The design of the packed lever assembly ensuresthat leakage does not occur when the valve is openor when back pressure is present.

Test gag

The test gag is used to prevent the safety valvefrom lifting. This is mainly used when carrying outa hydrostatic test on the system, duringcommissioning.

After testing, the test gag must be removed andreplaced with the sealing plug.

GAG SCREWSEALING PLUG

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*A lift lever can be used to test for correct valve operation where corrosion or deposits could prevent the valve fromopening.They can be used to release foreign particles trapped on the seat and must be fitted when codes dictate.

18

R E C O M M E N D E D M AT E R I A L T E M P E R AT U R E R A N G E S

BODY

1 Carbon steel SA 216-WCB –20 –29 800 427

2 Carbon steel (NACE) SA 216-WCB –20 –29 800 427

3 Stainless steel (NACE) SA 351-CF8M –450 –267 1000 538

4 Stainless steel SA 351-CF8M –450 –267 1000 538

5 Low Temp. CS (LT40) SA 352-LCB –50 –46 800 427

6 Bronze (Oxygen spec.) BS 1400 LG2 –450 –267 450 232

8 0.5% MOLY CS SA 217-WC6 –20 –29 1000 538

9 Hastelloy B SA 494-N12MV –20 –29 1000 538

SPRING

1 Carbon steel –75 –59 450 232

2 Stainless steel (316) –450 –267 500 260

6 Tungsten alloy (BH12) –4 –20 1000 538

9 Hastelloy B –20 –29 800 427

N Stainless steel (PH17/4) –130 –90 752 400

Q Stainless steel (PH17/4 NACE) –130 –90 752 400

Z Inconel X750 –450 –267 1000 538

TRIM (Nozzle and disc)

1 Stainless steel (PH 17/4 NACE 29-33 HRC) –130 –90 752 400

2 Stainless steel (316) –450 –267 1000 538

3 Al. Bronze/Monel –76 –60 572 300

4 Hastelloy B –20 –29 1000 538

5 Stainless steel (316 Stellited 39-43 HRC) –321 –196 1000 538

6 Monel –321 –196 800 427

7 Stainless steel 304 –238 –150 1000 538

GASKETS

NAF (ST-706) –40 –40 800 427

Graphite (Supergraf) –328 –200 932 500

Gylon 3504 –321 –196 260 260

SOFT SEAT

Nitrile –40 –40 212 100

Viton –22 –30 392 200

Silicon –85 –65 446 230

Ethylene Propylene –58 –50 275 135

PTFE –454 –270 428 220

Kalrez –20 –29 500 260

BOLTING

B7 Alloy steel –4 –20 800 427

B8T Stainless Steel –454 –270 1000 538

Monel K500 –274 –170 482 250

Description Minimum Maximumdeg F deg C deg F deg C

Notes1 All temperatures are at valve inlet.2 Trim items 1 and 5 are recommended for maximum durability.3 Alternative materials may be specified if agreed on enquiry.

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17

W B S E R I E S F I G U R E N U M B E R I N G S YS T E M

Body material1 Carbon steel WCB2 Carbon steel WCB NACE3 Stainless steel CF8M NACE4 Stainless steel CF8M5 Carbon steel low temperature LCB8 Carbon steel WC6 - 0.5% MolyO Special

Flange face1 ANSI RF x RF2 ANSI RTJ inlet x RFO Special

ANSI flange rating inlet x outlet1 150 x 1502 300 x 1503 600 x 1504 900 x 1505 900 x 3006 1500 x 1507 1500 x 3008 2500 x 300O Special

Valve type1 Liquid bellows2 Liquid conventional3 Vapour bellows4 Vapour conventional

DesignH ANSI 150, 300 and 600/ ANSI 900, 1500 and 2500

Outlet diameter2” - 10”

API orifice letterD - T

Inlet diameter1” - 8”

AccessoriesB Auxiliary

back-up pistonC Bolted capD Screwed capF Ferrule

(Government ring)G Test gagH* High PressureM Open leverP Packed leverR Soft seatV Open vented casingS Special feature

Trim material nozzle and disc1 Stainless steel PH 17/42 Stainless steel 3163 Aluminium bronze / Monel4 Hastelloy B5 Stainless steel 316 stellited6 Monel 7 Stainless steel 304O Special

Spring material1 Carbon steel 2 Stainless steel 3166 Tungsten alloy9 Hastelloy BA Aluminised CSN Stainless steel PH 17/4Q Stainless steel PH 17/4 NACEZ Inconel X750O Special

/

*In some instances whenboth high pressures andalloy springs are required,the ‘H’ needs adding toaccessories. See individualorifice pages.

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20

VA LV E S E L E C T I O N TA B L E – 0.110 in2

– 71 mm2D

1 1 x 2 150#RF 150#RF - - 285 185 80 - 285 230

2 1 x 2 300#RF 150#RF - - 740 615 410 - 285 230

3 1 x 2 600#RF 150#RF - - 1480 1235 825 - 285 230

4 11/2 x 2 900#RF 300#RF - - 2220 1845 1235 - 600 500

5 11/2 x 2 1500#RF 300#RF - - 3705 3080 2060 - 600 500

6 11/2 x 3 2500#RF 300#RF - - 6000 5135 3430 - 740 500

7 1 x 2 300#RF 150#RF - - - - 510 225 285 230

8 1 x 2 600#RF 150#RF - - - - 1015 445 285 230

9 11/2 x 2 900#RF 300#RF - - - - 1525 670 600 500

10 11/2 x 2 1500#RF 300#RF - - - - 2540 1115 600 500

11 11/2 x 3 2500#RF 300#RF - - - - 4230 1860 740 500

12 1 x 2 150#RF 150#RF 275 275 - - - - 275 230

13 1 x 2 300#RF 150#RF 720 720 - - - - 275 230

14 1 x 2 600#RF 150#RF 1440 1440 - - - - 275 230

15 11/2 x 2 900#RF 300#RF 2160 2160 - - - - 600 500

16 11/2 x 2 1500#RF 300#RF 3600 3600 - - - - 600 500

17 11/2 x 3 2500#RF 300#RF 4000 6000 - - - - 720 500

KeyNo. Inlet Outlet Body

Mat’l

-76°Fto

-450°F

-21°Fto

-75°F

100°Fto

-20°F450°F 800°F 1000°F

-60°Cto

-268°C

-30°Cto

-59°C

38°Cto

-29°C232°C 427°C 538°C

Co

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tio

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Val

ve

Bal

ance

dB

ello

ws V

alve

Valve sizeinlet x outlet

(ins)

Flanges ANSI Max. Set Pressure (psig)and Temperature Limits

Max. BackPressure

(psig)

RF=Raised Face

Note: Soft seated valves require a minimum set pressure of 15 psig.

High Pressure VersionThere is no requirement to have an high pressure version for this orifice.

Minimum set pressure limits for metal seat trim

Conventional – 7 psigBellows - Gas – 22 psig

Bellows - Liquid – 59 psig*

Conventional – 2 psig(Inverted)

WB

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*For liquid bellows valves below this pressure refer to factory

WCB

WC6

CF8M

19

VA LV E S E L E C T I O N C H A RT – 0.110 in2

– 71 mm2D

0

0 10 20 30 34.5 50 69 100 200 300 413.8

100 200 300 400 500 1000

1000

900

800

700

600

500

400

300

200

100

0

-100

-200

-300

-400-450 -268

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

450

500

538

2000 3000 4000 5000 6000

STA

INLE

SS

STE

EL

SS

- C

F8M

CA

RB

ON

STE

EL

- WC

B

CA

RB

ON

STE

EL

TUN

GS

TEN CS

- W

C6538 1000

427 800

232 450

-29 -20

-59 -75

-268 -450

7

1

171615141312

2 3 4 5 6

8 9 10 11

TEMPERATURELIMITS API 526

SP

RIN

G

BO

DY

SET PRESSURE - PSIG

SET PRESSURE - BAR G.

C

G(API)Drain Hole

H(API)Vent †

Cap

wit

hd

raw

al

A

D

B

E

F Size Rating A B C* D E F G H† Wt(ins) lbs (kg)

1 x 2 150 x 150 4.125 1.437 13.875 4.500 0.582 2 3/8 3/4 40 (18)300 x 150 4.125 1.437 13.875 4.500 0.582 2 3/8 3/4 40 (18)600 x 150 4.125 1.437 13.875 4.500 0.582 2 3/8 3/4 42 (19)

11/2 x 2 900 x 300 4.125 1.750 25.000 5.500 0.625 5 3/8 3/4 90 (41)1500 x 300 4.125 1.750 25.000 5.500 0.625 5 3/8 3/4 97 (44)

11/2 x 3 2500 x 300 5.500 2.375 26.875 7.000 0.625 5 3/8 3/4 115 (52)

* – If a gag is fitted, add 0.5 ins.– If a bellows is fitted in the 1 x 2 inch valve add 1.125 inch.– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)– For certified height (c), consult factory.

† Vent hole ‘H’ on bellows valves only.

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ORIFICE D (All dimensions in inches)

22

– 0.196 in2

– 127 mm2EVA LV E S E L E C T I O N TA B L E

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1 1 x 2 150#RF 150#RF - - 285 185 80 - 285 230

2 1 x 2 300#RF 150#RF - - 740 615 410 - 285 230

3 1 x 2 600#RF 150#RF - - 1480 1235 825 - 285 230

4 11/2 x 2 900#RF 300#RF - - 2220 1845 1235 - 600 500

5 11/2 x 2 1500#RF 300#RF - - 3705 3080 2060 - 600 500

6 11/2 x 3 2500#RF 300#RF - - 6000 5135 3430 - 740 500

7 1 x 2 300#RF 150#RF - - - - 510 225 285 230

8 1 x 2 600#RF 150#RF - - - - 1015 445 285 230

9 11/2 x 2 900#RF 300#RF - - - - 1525 670 600 500

10 11/2 x 2 1500#RF 300#RF - - - - 2540 1115 600 500

11 11/2 x 3 2500#RF 300#RF - - - - 4230 1860 740 500

12 1 x 2 150#RF 150#RF 275 275 - - - - 275 230

13 1 x 2 300#RF 150#RF 720 720 - - - - 275 230

14 1 x 2 600#RF 150#RF 1440 1440 - - - - 275 230

15 11/2 x 2 900#RF 300#RF 2160 2160 - - - - 600 500

16 11/2 x 2 1500#RF 300#RF 3600 3600 - - - - 600 500

17 11/2 x 3 2500#RF 300#RF 4000 6000 - - - - 720 500


Mat’l

-76°Fto

-450°F

-21°Fto

-75°F

100°Fto

-20°F450°F 800°F 1000°F

-60°Cto

-268°C

-30°Cto

-59°C

38°Cto

-29°C232°C 427°C 538°C

Co

nven

tio

nal

Val

ve

Bal

ance

dB

ello

ws V

alve


(ins)


Max. BackPressure

(psig)

RF=Raised Face








WCB

WC6

CF8M

21


– 127 mm2E

C

G(API)Drain Hole

H(API)Vent †

Cap

wit

hd

raw

al

A

D

B

E


1 x 2 150 x 150 4.125 1.437 13.875 4.500 0.582 2 3/8 3/4 40 (18)300 x 150 4.125 1.437 13.875 4.500 0.582 2 3/8 3/4 40 (18)600 x 150 4.125 1.437 13.875 4.500 0.582 2 3/8 3/4 42 (19)

11/2 x 2 900 x 300 4.125 1.750 25.000 5.500 0.625 5 3/8 3/4 90 (41)1500 x 300 4.125 1.750 25.000 5.500 0.625 5 3/8 3/4 97 (44)

11/2 x 3 2500 x 300 5.500 2.375 26.875 7.000 0.625 5 3/8 3/4 115 (52)

* – If a gag is fitted, add 0.5 ins.– If a bellows is fitted in the 1 x 2 inch valve add 1.125 inch.– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)– For certified height (c), consult factory.


0

0 10 20 30 34.5 50 69 100 200 300 413.8

100 200 300 400 500 1000

1000

900

800

700

600

500

400

300

200

100

0

-100

-200

-300

-400-450 -268

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

450

500

538

2000 3000 4000 5000 6000

STA

INLE

SS

STE

EL

SS

- C

F8M

CA

RB

ON

STE

EL

- WC

B

CA

RB

ON

STE

EL

TUN

GS

TEN CS

- W

C6538 1000

427 800

232 450

-29 -20

-59 -75

-268 -450

7

1

171615141312

2 3 4 5 6

8 9 10 11


SP

RIN

G

BO

DY

SET PRESSURE - PSIG


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ORIFICE E (All dimensions in inches)

24

– 0.307 in2

– 198 mm2FVA LV E S E L E C T I O N TA B L E


Mat’l

-76°Fto

-450°F

-21°Fto

-75°F

100°Fto

-20°F450°F 800°F 1000°F

-60°Cto

-268°C

-30°Cto

-59°C

38°Cto

-29°C232°C 427°C 538°C

Co

nven

tio

nal

Val

ve

Bal

ance

dB

ello

ws V

alve


(ins)


Max. BackPressure

(psig)


1 11/2 x 2 150#RF 150#RF - - 285 185 80 - 285 230

2 11/2 x 2 300#RF 150#RF - - 740 615 410 - 285 230

3 11/2 x 2 600#RF 150#RF - - 1480 1235 825 - 285 230

4 11/2 x 3 900#RF 300#RF - - 2220 1845 1235 - 740 500

5 11/2 x 3 1500#RF 300#RF - - 3705 3080 2060 - 740 500

6 11/2 x 3 2500#RF 300#RF - - 5000 5000 3430 - 740 500

7 11/2 x 2 300#RF 150#RF - - - - 510 225 285 230

8 11/2 x 2 600#RF 150#RF - - - - 1015 445 285 230

9 11/2 x 3 900#RF 300#RF - - - - 1525 670 740 500

10 11/2 x 3 1500#RF 300#RF - - - - 2540 1115 740 500

11 11/2 x 3 2500#RF 300#RF - - - - 4230 1860 740 500

12 11/2 x 2 150#RF 150#RF 275 275 - - - - 275 230

13 11/2 x 2 300#RF 150#RF 720 720 - - - - 275 230

14 11/2 x 2 600#RF 150#RF 1440 1440 - - - - 275 230

15 11/2 x 3 900#RF 300#RF 2160 2160 - - - - 720 500

16 11/2 x 3 1500#RF 300#RF 2200 3600 - - - - 720 500

17 11/2 x 3 2500#RF 300#RF 3400 5000 - - - - 720 500

WB

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RF=Raised Face






WCB

WC6

CF8M


23


– 198 mm2F

C

G(API)Drain Hole

H(API)Vent †

Cap

wit

hd

raw

al

A

D

B

E


11/2 x 2 150 x 150 4.875 1.625 14.625 4.750 0.750 2 3/8 3/4 46 (21)300 x 150 4.875 1.625 14.625 6.000 0.750 2 3/8 3/4 46 (21)600 x 150 4.875 1.625 14.625 6.000 0.750 2 3/8 3/4 46 (21)

11/2 x 3 900 x 300 4.875 1.750 26.750 6.500 0.500 5 3/8 3/4 101 (46)1500 x 300 4.875 1.750 26.750 6.500 0.500 5 3/8 3/4 101 (46)2500 x 300 5.500 2.375 26.875 7.000 0.625 5 3/8 3/4 117 (53)

0

0 10 20 30 40 48.3 69 200 344.8

100 200 300 400 500 600 700

1000

900

800

700

600

500

400

300

200

100

0

-100

-200

-300

-400-450 -268

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

450

500

538

1000 3000 5000

7

1

17

17

15141312

16

2 3 4 5 6

8 9 10 11

STA

INLE

SS

STE

EL

SS

- C

F8M

CA

RB

ON

STE

EL

- WC

B

CA

RB

ON

STE

EL

TUN

GS

TEN

CS

- W

C6538 1000

427 800

232 450

-29 -20

-59 -75

-268 -450


SP

RIN

G

BO

DY

SET PRESSURE - PSIG


* – If a gag is fitted, add 0.5 ins.– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)– For certified height (c), consult factory.


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ORIFICE F (All dimensions in inches)

26

– 0.503 in2

– 325 mm2GVA LV E S E L E C T I O N TA B L E


Mat’l

-76°Fto

-450°F

-21°Fto

-75°F

100°Fto

-20°F450°F 800°F 1000°F

-60°Cto

-268°C

-30°Cto

-59°C

38°Cto

-29°C232°C 427°C 538°C

Co

nven

tio

nal

Val

ve

Bal

ance

dB

ello

ws V

alve


(ins)


Max. BackPressure

(psig)

1 11/2 x 3 150#RF 150#RF - - 285 185 80 - 285 230

2 11/2 x 3 300#RF 150#RF - - 740 615 410 - 285 230

3 11/2 x 3 600#RF 150#RF - - 1480 1235 825 - 285 230

4 11/2 x 3 900#RF 300#RF - - 2220 1845 1235 - 740 470

5 2 x 3 1500#RF 300#RF - - 3705 3080 2060 - 740 470

6 2 x 3 2500#RF 300#RF - - 3705 3705 3430 - 740 470

7 11/2 x 3 300#RF 150#RF - - - - 510 225 285 230

8 11/2 x 3 600#RF 150#RF - - - - 1015 445 285 230

9 11/2 x 3 900#RF 300#RF - - - - 1525 670 740 470

10 2 x 3 1500#RF 300#RF - - - - 2540 1115 740 470

11 2 x 3 2500#RF 300#RF - - - - 3705 1860 740 470

12 11/2 x 3 150#RF 150#RF 275 275 - - - - 275 230

13 11/2 x 3 300#RF 150#RF 720 720 - - - - 275 230

14 11/2 x 3 600#RF 150#RF 1440 1440 - - - - 275 230

15 11/2 x 3 900#RF 300#RF 1600 2160 - - - - 720 470

16 2 x 3 1500#RF 300#RF 2450 3600 - - - - 720 470

17 2 x 3 2500#RF 300#RF 2600 3600 - - - - 720 470

WB

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RF=Raised Face






WCB

WC6

CF8M


25


– 325 mm2G

C

G(API)Drain Hole

H(API)Vent †

Cap

wit

hd

raw

al

A

D

B

E


11/2 x 3 150 x 150 4.875 1.312 18.750 4.750 0.500 2 3/8 3/4 60 (27)300 x 150 4.875 1.312 18.750 6.000 0.500 2 3/8 3/4 64 (29)600 x 150 4.875 1.437 18.750 6.000 0.500 2 3/8 3/4 66 (30)900 x 300 4.875 1.750 27.500 6.500 0.500 5 3/8 3/4 119 (54)

2 x 3 1500 x 300 6.125 2.125 32.000 6.750 0.500 5 1/2 3/4 126 (57)2500 x 300 6.125 2.812 32.000 6.750 0.687 2 1/2 3/4 139 (63)

STA

INLE

SS

STE

EL

SS

- C

F8M

CA

RB

ON

STE

EL

- WC

B

CA

RB

ON

STE

EL

TUN

GS

TEN

CS

- W

C6538 1000

427 800

232 450

-29 -20

-59 -75

-268 -450


SP

RIN

G

BO

DY

SET PRESSURE - PSIG


0

0 10 20 2001501006950 275.9

100 200 300 500

1000

900

800

700

600

500

400

300

200

100

0

-100

-200

-300

-400-450 -268

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

450

500

538

1000 30002000 4000

7

1

16 + 17

16

15

141312

2 3 4 5

6

8 9 10 11

17



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ORIFICE G (All dimensions in inches)

Inlet Max. Set Spring Material (pressures in Psig)

Orifice rating Pressure Psig Carbon st. 316 SS Tungsten 17/4PH 17/4PH NACE Inconel X750

1.5H 150# 285 n/a n/a n/a n/a n/a n/a

1.5H 300# 285 n/a n/a n/a n/a n/a n/a

2H 300# 740 n/a n/a n/a n/a n/a n/a

2H 600# 1480 n/a 1000 n/a n/a 1000 n/a

28

– 0.785 in2

– 506 mm2HVA LV E S E L E C T I O N TA B L E


Mat’l

-76°Fto

-450°F

-21°Fto

-75°F

100°Fto

-20°F450°F 800°F 1000°F

-60°Cto

-268°C

-30°Cto

-59°C

38°Cto

-29°C232°C 427°C 538°C

Co

nven

tio

nal

Val

ve

Bal

ance

dB

ello

ws V

alve


(ins)


Max. BackPressure

(psig)

1 11/2 x 3 150#RF 150#RF - - 285 185 80 - 285 230

2 11/2 x 3 300#RF 150#RF - - 285 285 285 - 285 230

3 2 x 3 300#RF 150#RF - - 740 615 410 - 285 230

4 2 x 3 600#RF 150#RF - - 1480 1235 825 - 285 230

5 2 x 3 900#RF 150#RF - - 2220 1845 1235 - 285 230

6 2 x 3 1500#RF 300#RF - - 2750 2750 2060 - 740 415

7 2 x 3 300#RF 150#RF - - - - 510 225 285 230

8 2 x 3 600#RF 150#RF - - - - 815 445 285 230

9 2 x 3 900#RF 150#RF - - - - 1225 670 285 230

10 2 x 3 1500#RF 300#RF - - - - 2040 1115 740 415

11 11/2 x 3 150#RF 150#RF 275 275 - - - - 275 230

12 11/2 x 3 300#RF 150#RF 275 275 - - - - 275 230

13 2 x 3 300#RF 150#RF 720 720 - - - - 275 230

14 2 x 3 600#RF 150#RF 1440 1440 - - - - 275 230

15 2 x 3 900#RF 150#RF 1485 2160 - - - - 275 230

16 2 x 3 1500#RF 300#RF 1600 2750 - - - - 720 415

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RF=Raised Face





High Pressure Version.Certain spring materials cannot be used in the low pressure version of the valve, up to the maximumpressure. If the required set pressure with your choice of spring material is in excess of the figure shown inthe table either choose another material or add “H” to the valve accessories to select an high pressure valve.

WCB

WC6

CF8M


27


– 506 mm2H

C

G(API)Drain Hole

H(API)Vent †

Cap

wit

hd

raw

al

A

D

B

E


11/2 x 3 150 x 150 5.125 1.375 18.750 4.875 0.500 2 3/8 3/4 60 (27)300 x 150 5.125 1.375 18.750 4.875 0.500 2 3/8 3/4 60 (27)

2 x 3 300 x 150 5.125 1.375 19.000 4.875 0.500 2 3/8 3/4 64 (29)600 x 150 6.062 1.687 20.000 6.375 0.687 2 3/8 3/4 86 (39)900 x 150 6.062 2.312 31.750 6.375 0.687 5 1/2 3/4 176 (80)

1500 x 300 6.062 2.375 32.000 6.375 0.750 5 1/2 3/4 187 (85)

STA

INLE

SS

STE

EL

SS

- C

F8M

CA

RB

ON

STE

EL

- WC

B

CA

RB

ON

STE

EL

TUN

GS

TEN

CS

- W

C6538 1000

427 800

232 450

-29 -20

-59 -75

-268 -450


SP

RIN

G

BO

DY

SET PRESSURE - PSIG


0

0 10 20 30 34.5 50 69 100 150 206.9

100 200 300 400 500

1000

900

800

700

600

500

400

300

200

100

0

-100

-200

-300

-400-450 -268

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

450

500

538

1000 2000 3000

7

1

11 + 12 13 14

15

16

2

3 4 5 6

8 9 10



WB

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ORIFICE H (All dimensions in inches)

3029


– 830 mm2J – 1.287 in2

– 830 mm2J

C

G(API)Drain Hole

H(API)Vent †

Cap

wit

hd

raw

al

A

D

B

E


2 x 3 150 x 150 5.375 1.625 19.250 4.875 0.750 2 3/8 3/4 64 (29)300 x 150 5.375 1.625 19.250 4.875 0.750 2 3/8 3/4 64 (29)

3 x 4 300 x 150 7.250 2.125 21.750 7.125 0.750 2 3/8 3/4 82 (37)600 x 150 7.250 2.175 23.000 7.125 0.750 2 3/8 3/4 99 (45)900 x 150 7.250 2.375 33.875 7.125 0.750 5 1/2 3/4 231 (105)

1500 x 300 7.250 2.750 33.875 7.125 0.750 5 1/2 3/4 253 (115)

16

0

0 10 20 30 34.5 50 69 100 150 206.9

100 200 300 400 500

1000

900

800

700

600

500

400

300

200

100

0

-100

-200

-300

-400-450 -268

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

450

500

538

1000 2000 3000

7

1

11 + 12 1413 15 +16

2

3 4 5 6

108 9

STA

INLE

SS

STE

EL

SS

- C

F8M

CA

RB

ON

STE

EL

- WC

B

CA

RB

ON

STE

EL

TUN

GS

TEN

CS

- W

C6538 1000

427 800

232 450

-29 -20

-59 -75

-268 -450


SP

RIN

G

BO

DY

SET PRESSURE - PSIG


14 15

VA LV E S E L E C T I O N TA B L E


Mat’l

-76°Fto

-450°F

-21°Fto

-75°F

100°Fto

-20°F450°F 800°F 1000°F

-60°Cto

-268°C

-30°Cto

-59°C

38°Cto

-29°C232°C 427°C 538°C

Co

nven

tio

nal

Val

ve

Bal

ance

dB

ello

ws V

alve


(ins)


Max. BackPressure

(psig)

1 2 x 3 150#RF 150#RF - - 285 185 80 - 285 230

2 2 x 3 300#RF 150#RF - - 285 285 285 - 285 230

3 3 x 4 300#RF 150#RF - - 740 615 410 - 285 230

4 3 x 4 600#RF 150#RF - - 1480 1235 825 - 285 230

5 3 x 4 900#RF 150#RF - - 2220 1845 1235 - 285 230

6 3 x 4 1500#RF 300#RF - - 2700 2700 2060 - 600 230

7 3 x 4 300#RF 150#RF - - - - 510 225 285 230

8 3 x 4 600#RF 150#RF - - - - 815 445 285 230

9 3 x 4 900#RF 150#RF - - - - 1225 670 285 230

10 3 x 4 1500#RF 300#RF - - - - 2040 1115 600 230

11 2 x 3 150#RF 150#RF 275 275 - - - - 275 230

12 2 x 3 300#RF 150#RF 275 275 - - - - 275 230

13 3 x 4 300#RF 150#RF 500 720 - - - - 275 230

14 3 x 4 600#RF 150#RF 625 1440 - - - - 275 230

15 3 x 4 900#RF 150#RF 800 2160 - - - - 275 230

16 3 x 4 1500#RF 300#RF 800 2700 - - - - 600 230



WB

SE

RIE

S

WB

SE

RIE

S

ORIFICE J (All dimensions in inches) Note: Soft seated valves require a minimum set pressure of 15 psig.

RF=Raised Face




Conventional – 1.5 psig(Inverted)



2J 150# 285 n/a n/a n/a n/a n/a n/a

2J 300# 285 n/a n/a n/a n/a n/a n/a

3J 300# 740 n/a 500 n/a n/a 430 n/a

3J 600# 1480 n/a 900 n/a 900 870 900


WCB

WC6

CF8M


32

– 1.838 in2

– 1185 mm2KVA LV E S E L E C T I O N TA B L E


Mat’l

-76°Fto

-450°F

-21°Fto

-75°F

100°Fto

-20°F450°F 800°F 1000°F

-60°Cto

-268°C

-30°Cto

-59°C

38°Cto

-29°C232°C 427°C 538°C

Co

nven

tio

nal

Val

ve

Bal

ance

dB

ello

ws V

alve


(ins)


Max. BackPressure

(psig)

1 3 x 4 150#RF 150#RF - - 285 185 80 - 285 150

2 3 x 4 300#RF 150#RF - - 740 615 410 - 285 150

3 3 x 4 600#RF 150#RF - - 1480 1235 825 - 285 200

4 3 x 6 900#RF 150#RF - - 2220 1845 1235 - 285 200

5 3 x 6 1500#RF 300#RF - - 2220 2220 2060 - 600 200

6 3 x 4 300#RF 150#RF - - - - 510 215 285 150

7 3 x 4 600#RF 150#RF - - - - 815 445 285 200

8 3 x 6 900#RF 150#RF - - - - 1225 670 285 200

9 3 x 6 1500#RF 300#RF - - - - 2040 1115 600 200

10 3 x 4 150#RF 150#RF 275 275 - - - - 275 150

11 3 x 4 300#RF 150#RF 525 720 - - - - 275 150

12 3 x 4 600#RF 150#RF 600 1440 - - - - 275 200

13 3 x 6 900#RF 150#RF 600 2160 - - - - 275 200

14 3 x 6 1500#RF 300#RF 750 2220 - - - - 600 200

WB

SE

RIE

S


RF=Raised Face







K 150# 285 n/a n/a n/a n/a n/a n/a

K 300# 740 n/a 450 n/a n/a 600 n/a

K 600# 1480 n/a 750 n/a n/a 570 1070

High Pressure Version.Certain spring materials can not be used in the low pressure version of the valve, up to the maximumpressure. If the required set pressure with your choice of spring material is in excess of the figure shown inthe table either choose another material or add “H” to the valve accessories to select an high pressure valve.

WCB

WC6

CF8M


31


– 1185 mm2K

C

G(API)Drain Hole

H(API)Vent †

Cap

wit

hd

raw

al

A

D

B

E


3 x 4 150 x 150 6.125 2.000 21.750 6.375 0.875 3 3/8 3/4 108 (49)300 x 150 6.125 2.000 21.750 6.375 0.875 3 3/8 3/4 108 (49)600 x 150 7.250 2.125 23.500 7.125 0.875 3 3/8 3/4 141 (64)

3 x 6 900 x 150 7.812 2.562 40.000 8.500 0.937 5 3/4 3/4 339 (154)1500 x 300 7.750 2.875 40.000 8.500 0.875 5 3/4 3/4 353 (160)

0

0 10 20 30 40 48.3 69 100 150 206.9

100 200 300 400 500 600 700

1000

900

800

700

600

500

400

300

200

100

0

-100

-200

-300

-400-450 -268

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

450

500

538

1000 2000 3000

INC

ON

EL

6

1

12 13

12+13

1410 11

2 3 4

5

97 8

STA

INLE

SS

STE

EL

SS

- C

F8M

CA

RB

ON

STE

EL

- WC

B

CA

RB

ON

STE

EL

TUN

GS

TEN

CS

- W

C6538 1000

427 800

232 450

-29 -20

-59 -75

-268 -450


SP

RIN

G

BO

DY

SET PRESSURE - PSIG


14



WB

SE

RIE

S

ORIFICE K (All dimensions in inches)

34

– 2.853 in2

– 1840 mm2LVA LV E S E L E C T I O N TA B L E


Mat’l

-76°Fto

-450°F

-21°Fto

-75°F

100°Fto

-20°F450°F 800°F 1000°F

-60°Cto

-268°C

-30°Cto

-59°C

38°Cto

-29°C232°C 427°C 538°C

Co

nven

tio

nal

Val

ve

Bal

ance

dB

ello

ws V

alve


(ins)


Max. BackPressure

(psig)

1 3 x 4 150#RF 150#RF - - 285 185 80 - 285 100

2 3 x 4 300#RF 150#RF - - 285 285 285 - 285 100

3 4 x 6 300#RF 150#RF - - 740 615 410 - 285 170

4 4 x 6 600#RF 150#RF - - 1000 1000 825 - 285 170

5 4 x 6 900#RF 150#RF - - 1500 1500 1235 - 285 170

6 4 x 6 1500#RF 150#RF - - 1500 1500 1500 - 285 170

7 4 x 6 300#RF 150#RF - - - - 510 225 285 170

8 4 x 6 600#RF 150#RF - - - - 1000 445 285 170

9 4 x 6 900#RF 150#RF - - - - 1500 670 285 170

10 4 x 6 1500#RF 150#RF - - - - 1500 1115 285 170

11 3 x 4 150#RF 150#RF 275 275 - - - - 275 100

12 3 x 4 300#RF 150#RF 275 275 - - - - 275 100

13 4 x 6 300#RF 150#RF 535 720 - - - - 275 170

14 4 x 6 600#RF 150#RF 535 1000 - - - - 275 170

15 4 x 6 900#RF 150#RF 700 1500 - - - - 275 170

WB

SE

RIE

S


RF=Raised Face







3L 150# 285 n/a n/a n/a n/a 255 n/a

3L 300# 285 n/a n/a n/a n/a 255 n/a

4L 300# 740 n/a n/a n/a n/a n/a n/a

4L 600# 1480 850 n/a n/a n/a 825 n/a


WCB

WC6

CF8M


33


– 1840 mm2L

C

G(API)Drain Hole

H(API)Vent †

Cap

wit

hd

raw

al

A

D

B

E


3 x 4 150 x 150 6.125 2.000 21.750 6.500 0.875 4 3/8 3/4 108 (49)300 x 150 6.125 2.000 21.750 6.500 0.875 4 3/8 3/4 108 (49)

4 x 6 300 x 150 7.062 2.062 27.000 7.125 0.812 5 1/2 1 234 (106)600 x 150 7.062 2.312 28.250 8.000 0.812 5 1/2 1 249 (113)900 x 150 7.750 2.687 41.875 8.750 0.750 5 1/2 1 353 (160)

1500 x 150 7.750 2.937 44.000 8.750 0.812 5 1/2 1 361 (164)

0

0 10 4030 5040 60 6920 103.5

200 400 600 800

1000

900

800

700

600

500

400

300

200

100

0

-100

-200

-300

-400-450 -268

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

450

500

538

1000 1500

7

1

1413

13 + 14 1511 + 12

2

3 4 5

6

8 9 10S

TAIN

LES

S S

TEE

L

SS

- C

F8M

CA

RB

ON

STE

EL

- WC

B

CA

RB

ON

STE

EL

TUN

GS

TEN

CS

- W

C6538 1000

427 800

232 450

-29 -20

-59 -75

-268 -450


SP

RIN

G

BO

DY

SET PRESSURE - PSIG


15



WB

SE

RIE

S

ORIFICE L (All dimensions in inches)

36

– 3.60 in2

– 2320 mm2MVA LV E S E L E C T I O N TA B L E


Mat’l

-76°Fto

-450°F

-21°Fto

-75°F

100°Fto

-20°F450°F 800°F 1000°F

-60°Cto

-268°C

-30°Cto

-59°C

38°Cto

-29°C232°C 427°C 538°C

Co

nven

tio

nal

Val

ve

Bal

ance

dB

ello

ws V

alveValve sizeinlet x outlet

(ins)


Max. BackPressure

(psig)

1 4 x 6 150#RF 150#RF - - 285 185 80 - 285 80

2 4 x 6 300#RF 150#RF - - 740 615 410 - 285 160

3 4 x 6 600#RF 150#RF - - 1100 1100 825 - 285 160

4 4 x 6 900#RF 150#RF - - 1100 1100 1100 - 285 160

5 4 x 6 300#RF 150#RF - - - - 510 225 285 160

6 4 x 6 600#RF 150#RF - - - - 1015 445 285 160

7 4 x 6 900#RF 150#RF - - - - 1100 670 285 160

8 4 x 6 150#RF 150#RF 275 275 - - - - 275 80

9 4 x 6 300#RF 150#RF 525 720 - - - - 275 160

10 4 x 6 600#RF 150#RF 600 1000 - - - - 275 160

WB

SE

RIE

S


RF=Raised Face







M 150# 285 n/a n/a n/a n/a n/a n/a

M 300# 740 n/a 500 n/a n/a 590 n/a

M 600# 1110 n/a 825 n/a n/a 900 1000


WCB

WC6

CF8M


35


– 2320 mm2M

C

G(API)Drain Hole

H(API)Vent †

Cap

wit

hd

raw

al

A

D

B

E


4 x 6 150 x 150 7.000 2.000 26.500 7.250 0.750 5 1/2 1 234 (106)300 x 150 7.000 2.000 26.500 7.250 0.750 5 1/2 1 234 (106)600 x 150 7.000 2.250 28.250 8.000 0.750 5 1/2 1 249 (113)900 x 150 7.750 2.500 41.875 8.750 0.750 5 1/2 1 377 (171)

0

0 10 4030 5040 60 6920 103.5

200 400 600 800

1000

900

800

700

600

500

400

300

200

100

0

-100

-200

-300

-400-450 -268

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

450

500

538

1000 1500

INC

ON

EL

5

1

10

98 10

2 3

4

6 7

STA

INLE

SS

STE

EL

SS

- C

F8M

CA

RB

ON

STE

EL

- WC

B

CA

RB

ON

STE

EL

TUN

GS

TEN

CS

- W

C6538 1000

427 800

232 450

-29 -20

-59 -75

-268 -450


SP

RIN

G

BO

DY

SET PRESSURE - PSIG




WB

SE

RIE

S

ORIFICE M (All dimensions in inches)

3837

VA LV E S E L E C T I O N C H A RT – 4.34 ins2

– 2800 mm2N – 4.34 ins2

– 2800 mm2N

C

G(API)Drain Hole

H(API)Vent †

Cap

wit

hd

raw

al

A

D

B

E


4 x 6 150 x 150 7.750 2.000 29.250 8.250 0.750 5 1/2 1 242 (110)300 x 150 7.750 2.000 29.250 8.250 0.750 5 1/2 1 242 (110)600 x 150 7.750 2.250 34.250 8.750 0.750 5 1/2 1 258 (117)900 x 150 7.750 2.500 41.500 8.750 0.750 5 1/2 1 395 (179)

0

0 10 30 5040 60 6920

200 400 600 800

1000

900

800

700

600

500

400

300

200

100

0

-100

-200

-300

-400-450 -268

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

450

500

538

1000

5

1

10

98 10

2 3

4

6 7S

TAIN

LES

S S

TEE

L

SS

- C

F8M

CA

RB

ON

STE

EL

- WC

B

CA

RB

ON

STE

EL

TUN

GS

TEN

CS

- W

C6538 1000

427 800

232 450

-29 -20

-59 -75

-268 -450


SP

RIN

G

BO

DY

SET PRESSURE - PSIG




Mat’l

-76°Fto

-450°F

-21°Fto

-75°F

100°Fto

-20°F450°F 800°F 1000°F

-60°Cto

-268°C

-30°Cto

-59°C

38°Cto

-29°C232°C 427°C 538°C

Co

nven

tio

nal

Val

ve

Bal

ance

dB

ello

ws V

alve


(ins)


Max. BackPressure

(psig)

1 4 x 6 150#RF 150#RF - - 285 185 80 - 285 80

2 4 x 6 300#RF 150#RF - - 740 615 410 - 285 160

3 4 x 6 600#RF 150#RF - - 1000 1000 825 - 285 160

4 4 x 6 900#RF 150#RF - - 1000 1000 1000 - 285 160

5 4 x 6 300#RF 150#RF - - - - 510 225 285 160

6 4 x 6 600#RF 150#RF - - - - 1000 445 285 160

7 4 x 6 900#RF 150#RF - - - - 1000 670 285 160

8 4 x 6 150#RF 150#RF 275 275 - - - - 275 80

9 4 x 6 300#RF 150#RF 450 720 - - - - 275 160

10 4 x 6 600#RF 150#RF 500 1000 - - - - 275 160



WB

SE

RIE

S

WB

SE

RIE

S

ORIFICE N (All dimensions in inches)


RF=Raised Face







N 150# 285 n/a n/a n/a n/a n/a n/a

N 300# 740 n/a 680 n/a n/a 700 n/a

N 600# 1000 n/a n/a n/a n/a n/a n/a


WCB

WC6

CF8M


40

– 6.38 ins2

– 4120 mm2PVA LV E S E L E C T I O N TA B L E


Mat’l

-76°Fto

-450°F

-21°Fto

-75°F

100°Fto

-20°F450°F 800°F 1000°F

-60°Cto

-268°C

-30°Cto

-59°C

38°Cto

-29°C232°C 427°C 538°C

Co

nven

tio

nal

Val

ve

Bal

ance

dB

ello

ws V

alve


(ins)


Max. BackPressure

(psig)

1 4 x 6 150#RF 150#RF - - 285 185 80 - 285 80

2 4 x 6 300#RF 150#RF - - 525 525 410 - 285 150

3 4 x 6 600#RF 150#RF - - 1000 1000 825 - 285 150

4 4 x 6 900#RF 150#RF - - 1000 1000 1000 - 285 150

5 4 x 6 300#RF 150#RF - - - - 510 225 285 150

6 4 x 6 600#RF 150#RF - - - - 1000 445 285 150

7 4 x 6 900#RF 150#RF - - - - 1000 670 285 150

8 4 x 6 150#RF 150#RF 175 275 - - - - 275 80

9 4 x 6 300#RF 150#RF 300 525 - - - - 275 150

10 4 x 6 600#RF 150#RF 480 1000 - - - - 275 150

WB

SE

RIE

S


RF=Raised Face







P 150# 285 n/a n/a n/a n/a n/a n/a

P 300# 525 n/a 350 n/a n/a 390 460

P 600# 1000 n/a 640 n/a n/a 336 n/a


WCB

WC6

CF8M


39

VA LV E S E L E C T I O N C H A RT – 6.38 ins2

– 4120 mm2P

C

G(API)Drain Hole

H(API)Vent †

Cap

wit

hd

raw

al

A

D

B

E


4 x 6 150 x 150 7.125 2.000 27.750 9.000 0.750 5 1/2 1 254 (115)300 x 150 8.875 2.000 29.250 10.000 0.750 5 1/2 1 254 (115)600 x 150 8.875 2.250 35.250 10.000 0.750 5 1/2 1 269 (122)900 x 150 8.875 2.500 45.000 10.000 0.750 5 1/2 1 412 (187)

0

0 10 30 5040 60 6920

200 400 600 800

1000

900

800

700

600

500

400

300

200

100

0

-100

-200

-300

-400-450 -268

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

450

500

538

1000

INC

ON

EL

5

1

10

98 10

2 3

4

6 7S

TAIN

LES

S S

TEE

L

SS

- C

F8M

CA

RB

ON

STE

EL

- WC

B

CA

RB

ON

STE

EL

TUN

GS

TEN

CS

- W

C6538 1000

427 800

232 450

-29 -20

-59 -75

-268 -450


SP

RIN

G

BO

DY

SET PRESSURE - PSIG




WB

SE

RIE

S

ORIFICE P (All dimensions in inches)

42

– 11.05 in2

– 7130 mm2QVA LV E S E L E C T I O N TA B L E


Mat’l

-76°Fto

-450°F

-21°Fto

-75°F

100°Fto

-20°F450°F 800°F 1000°F

-60°Cto

-268°C

-30°Cto

-59°C

38°Cto

-29°C232°C 427°C 538°C

Co

nven

tio

nal

Val

ve

Bal

ance

dB

ello

ws

Val

ve


(ins)


Max. BackPressure

(psig)

1 6 x 8 150#RF 150#RF - - 165 165 80 - 115 70

2 6 x 8 300#RF 150#RF - - 300 300 300 - 115 115

3 6 x 8 600#RF 150#RF - - 600 600 600 - 115 115

4 6 x 8 300#RF 150#RF - - - - 165 165 115 115

5 6 x 8 600#RF 150#RF - - - - 600 445 115 115

6 6 x 8 150#RF 150#RF 165 165 - - - - 115 70

7 6 x 8 300#RF 150#RF 250 300 - - - - 115 115

8 6 x 8 600#RF 150#RF 300 600 - - - - 115 115

WB

SE

RIE

S


RF=Raised Face







Q 150# 165 n/a 109 n/a n/a 117 n/a

Q 300# 300 n/a 109 n/a 165 117 165

Q 600# 600 n/a 0 n/a 400 0 390


WCB

WC6

CF8M


41


– 7130 mm2Q

C

G(API)Drain Hole

H(API)Vent †

Cap

wit

hd

raw

al

A

D

B

E


6 x 8 150 x 150 9.437 2.312 31.750 9.500 0.812 3 1/2 1 364 (165)300 x 150 9.437 2.312 31.750 9.500 0.812 3 1/2 1 364 (165)600 x 150 9.437 2.750 36.750 9.500 0.812 6 1/2 1 399 (181)

0

0 41.4302015106.96420.69

10 50 100 200 300 400 500

1000

900

800

700

600

500

400

300

200

100

0

-100

-200

-300

-400-450 -268

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

450

500

538

600

54

1

8

876

2 3

STA

INLE

SS

STE

EL

SS

- C

F8M

CA

RB

ON

STE

EL

- WC

B

CA

RB

ON

STE

EL

TUN

GS

TEN

CS

- W

C6538 1000

427 800

232 450

-29 -20

-59 -75

-268 -450


SP

RIN

G

BO

DY

SET PRESSURE - PSIG



† Vent hole ‘H’ on bellows valves only.WB

SE

RIE

S

ORIFICE Q (All dimensions in inches)

44

– 16.00 in2

– 10300 mm2RVA LV E S E L E C T I O N TA B L E


Mat’l

-76°Fto

-450°F

-21°Fto

-75°F

100°Fto

-20°F450°F 800°F 1000°F

-60°Cto

-268°C

-30°Cto

-59°C

38°Cto

-29°C232°C 427°C 538°C

Co

nven

tio

nal

Val

ve

Bal

ance

dB

ello

ws V

alveValve sizeinlet x outlet

(ins)


Max. BackPressure

(psig)

1 6 x 8 150#RF 150#RF - - 100 100 80 - 60 60

2 6 x 8 300#RF 150#RF - - 100 100 100 - 60 60

3 6 x 10 300#RF 150#RF - - 230 230 230 - 100 100

4 6 x 10 600#RF 150#RF - - 300 300 300 - 100 100

5 6 x 8 300#RF 150#RF - - - - 100 100 60 60

6 6 x 10 600#RF 150#RF - - - - 300 300 100 100

7 6 x 8 150#RF 150#RF 55 100 - - - - 60 60

8 6 x 8 300#RF 150#RF 55 100 - - - - 60 60

9 6 x 10 300#RF 150#RF 150 230 - - - - 100 100

10 6 x 10 600#RF 150#RF 200 300 - - - - 100 100

WB

SE

RIE

S


RF=Raised Face







6R8 150# 100 n/a 73 n/a n/a 90 n/a

6R8 300# 100 n/a 73 n/a n/a 90 n/a

6R10 300# 230 n/a 73 n/a 224 90 147

6R10 600# 300 n/a 190 n/a n/a 180 n/a


WCB

WC6

CF8M


43


– 10300 mm2R

C

G(API)Drain Hole

H(API)Vent †

Cap

wit

hd

raw

al

A

D

B

E


6 x 8 150 x 150 9.437 2.312 34.750 9.500 0.812 3 1/2 1 370 (168)300 x 150 9.437 2.312 34.750 9.500 0.812 3 1/2 1 370 (168)

6 x 10 300 x 150 9.437 2.312 34.750 10.500 0.812 3 1/2 1 465 (211)600 x 150 9.437 2.750 40.750 10.500 0.812 6 1/2 1 489 (222)

0

0 20.715106.953.45321

10 3020 40 50 100 200

1000

900

800

700

600

500

400

300

200

100

0

-100

-200

-300

-400-450 -268

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

450

500

538

300

65

1

10

1097 + 8

3 4

2

STA

INLE

SS

STE

EL

SS

- C

F8M

CA

RB

ON

STE

EL

- WC

B

CA

RB

ON

STE

EL

TUN

GS

TEN

CS

- W

C6538 1000

427 800

232 450

-29 -20

-59 -75

-268 -450


SP

RIN

G

BO

DY

SET PRESSURE - PSIG




WB

SE

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ORIFICE R (All dimensions in inches)

4645


– 16770 mm2T – 26.00 in2

– 16770 mm2T

C

G(API)Drain Hole

H(API)Vent †

Cap

wit

hd

raw

al

A

D

B

E


8 x 10 150 x150 10.875 2.625 42.250 11.000 1.000 6 1/2 1 661 (300)300 x 150 10.875 2.625 42.250 11.000 1.000 6 1/2 1 683 (310)

0

0 20.71 65432 6.9

10 3020 40 50 60 70 80 90 100 200

1000

900

800

700

600

500

400

300

200

100

0

-100

-200

-300

-400-450 -268

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

450

500

538

300

3

1

54

5

2

STA

INLE

SS

STE

EL

SS

- C

F8M

CA

RB

ON

STE

EL

- WC

B

CA

RB

ON

STE

EL

TUN

GS

TEN

CS

- W

C6538 1000

427 800

232 450

-29 -20

-59 -75

-268 -450


SP

RIN

G

BO

DY

SET PRESSURE - PSIG




Mat’l

-76°Fto

-450°F

-21°Fto

-75°F

100°Fto

-20°F450°F 800°F 1000°F

-101°Cto

-60°C

-60°Cto

-268°C

38°Cto

-29°C232°C 427°C 538°C

Co

nven

tio

nal

Val

ve

Bal

ance

dB

ello

ws

Val

ve


(ins)


Max. BackPressure

(psig)

1 8 x 10 150#RF 150#RF - - 65 65 65 - 30 30

2 8 x 10 300#RF 150#RF - - 300 300 300 - 100 100

3 8 x 10 300#RF 150#RF - - - - 300 225 100 100

4 8 x 10 150#RF 150#RF 50 65 - - - - 30 30

5 8 x 10 300#RF 150#RF 65 120 - - - - 60 60


† Vent hole ‘H’ on bellows valves only.WB

SE

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WB

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ORIFICE T (All dimensions in inches)


RF=Raised Face







T 150# 65 n/a n/a n/a n/a n/a n/a

T 300# 300 200 79 200 138 96 83


WCB

WC6

CF8M


48

B L OW- D OW N R I N G S E T T I N G

The blow-down adjustment is achieved by meansof a single blowdown ring.

By reducing the blow-down gap,blow-down is increased.

By increasing the blow-down gap,blow-down is decreased.

Blow-down is defined as the difference betweenthe set pressure of the valve and the reseatingpressure.

ImportantIt is important to reset the blow-down ring tothe correct position after maintenance hasbeen carried out on the valve.

Method

1) Removing the setting screw in the body permitsaccess to the blow-down ring.

2) Close the blow-down gap until the ring istouching the face of the disc (turn the ring fromleft to right).

3) Consult the chart in the maintenance manual todetermine the correct blow-down ring setting,or consult the factory.

4) Wind back the blow-down ring the right numberof notches to establish the correct position(count the number of notches or serrations onthe outside of the blow-down ring).

5) Relocate the locking pin into the notchesprovided on the outside diameter of the blow-down ring.

6) Tighten up the setting screw, ensuring that anundamaged gasket is in place.

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Blow-down Ring

Setting Screw

BDR Notches

AdjustableBlow-downGap

Note: It is dangerous to adjust the blow-downring when the valve is under pressure, unless asuitable ‘test gag’ is fitted to prevent inadvertentvalve opening

47

Each valve is factory set and normally would notneed any pressure adjustment; however, if theoccasion arises, the following procedures apply:

ASMEIf the valve is ASME stamped (UV)(NB), repairsmust be carried out by an ASME authorised repaircompany, i.e. one holding either the (UV) or (VR)stamp.

Test rigIt is normally desirable to remove the valve fromthe plant and use a suitable test rig, specificallydesigned for safety relief valves.

RangeEach spring has a definite range, the limits of whichshould not be exceeded.These should be checkedwith the factory, since if a set pressure change isrequired, it may be necessary to obtain a newspring. Should the set pressure be changed it isimportant to ensure that the valve will still havesufficient capacity under the new serviceconditions.

Procedure

1) Remove the cap (3).This exposes thecompression screw (12).

2) Slacken the locknut (13).

3) Introduce pressure to the valve inlet.The springpressure and consequently the valve setpressure may be increased or decreased byturning the compression screw.

P R E S S U R E A D J U S T M E N T

C O L D D I F F E R E N T I A L T E S T P R E S S U R E

When setting a valve intended for use at hightemperature on a test rig using a test fluid atambient temperatures, it is necessary to setthe valve at a slightly higher pressure, so thatit will open at the correct set pressure underoperating conditions.The necessary allowanceis shown in the following table.

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Operating Operating % Increase in settemperature – temperature – pressure at ambient

Centigrade Fahrenheit temperature

Up to 121°C Up to 250°F None

122°C to 316°C 251°F to 600°F 1

317°C to 427°C 601°F to 800°F 2

428°C to 538°C 801°F to 1000°F 3

3

13

12

Clockwise - increases set pressure

Anti-clockwise - decreases set pressure

Check against a calibrated pressure gauge.

4) Re-tighten the locknut and refit the cap.Replace cap gasket if damaged.

5) Check seat leakage (see page 49/50).

50

(in accordance with API 527)

S E AT T I G H T N E S S / S E AT L E A K AG E T E S T I N G

TESTING WITH STEAM TESTING WITH WATER

S1 Test MediumThe test medium shall be saturated steam.

S2 Test configurationThe valve shall be vertically mounted on the steamtest stand.

S3 Test PressureFor a valve whose set pressure is greater than50 Psig, the seat tightness shall be determinedwith the test pressure at the valve inlet held at90% of the set pressure. For a valve set at 50 Psigor less, the test pressure shall be held at5 Psig less than the set pressure.

S4 Leakage TestBefore starting the seat tightness test, the setpressure shall be demonstrated and the testpressure shall be held for at least 3 minutes.Anycondensate in the body bowl shall be removedbefore the seat tightness test. Air (or nitrogen)may be used to dissipate condensate.

After any condensate has been removed, the inletpressure shall be increased to the test pressure.Tightness shall then be checked visually using ablack background.

The valve shall then be observed for leakage for atleast 1 minute.

S5 Acceptance CriteriaFor both metal and soft-seated valves, there shallbe no audible or visible leakage for 1 minute.

IMPORTANT– ALL LIQUID TRIM VALVESMUST BE TESTED ON WATER.OTHERWISE SET PRESSURES ANDLEAKAGE RATE RESULTS WILL BE FALSE.

W1 Test MediumThe test medium shall be water near ambienttemperature.

W2 Test configurationThe valve shall be vertically mounted on the watertest stand.

W3 Test PressureFor a valve whose set pressure is greater than50 Psig, the seat tightness shall be determinedwith the test pressure at the valve inlet held at90% of the set pressure. For a valve set at 50 Psigor less, the test pressure shall be held at5 Psig less than the set pressure.

W4 Leakage TestBefore starting the seat tightness, the set pressureshall be demonstrated and the outlet body bowlshall be filled with water.The pressure gauge shallbe allowed to stabilise with no visible flow fromthe valve outlet.The inlet pressure shall then beincreased to the test pressure.The valve shall thenbe observed for 1 minute at the test pressure.

W5 Acceptance CriteriaFor a metal-seated valve whose inlet has a nominalpipe-size of 1 inch or larger, the leakage rate shallnot exceed 10 cubic centimetres per hour per inchof nominal inlet size. For a metal-seated valvewhose inlet has a nominal pipe size of less than 1 inch, the leakage rate shall not exceed 10 cubiccentimetres per hour. For soft-seated valves, thereshall be no leakage for 1 minute.

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IMPORTANT: Test rig cleanlines is vital to avoid contamination and damage to the safety reliefvalve seat surfaces.

49

S E AT T I G H T N E S S / S E AT L E A K AG E T E S T I N G

Described here are methods of determining theseat tightness of metal and soft-seated pressurerelief valves, including those of conventional,bellows and pilot-operated designs.

The maximum acceptable leakage rates are definedfor pressure relief valves with set pressures from15 Psig to 6,000 Psig. If greater seat tightness isrequired, the purchaser shall specify it in thepurchase order.

The test medium for determining the seat tightness- air, steam or water - shall be the same as thatused for determining the set pressure of the valve.

For dual-service valves, the test medium - air, steamor water - shall be the same as the primaryrelieving medium.

To ensure safety, the procedures outlined shall beperformed by persons experienced in the use andfunctions of pressure relief valves.

(in accordance with API 527)

TESTING WITH AIR

A1 Test ApparatusA test arrangement for determining seat tightnesswith air is shown opposite. Leakage shall bemeasured using a tube with an outside diameter of5/16 inch and a wall thickness of 0.035 inch.Thetube end shall be cut square and smooth.The tubeopening shall be 1⁄2 inch below the surface of thewater. The tube shall be perpendicular to thesurface of the water.

A2 Test MediumThe test medium shall be air (or nitrogen) nearambient temperature.

A3 Test configurationThe valve shall be vertically mounted on the teststand and the test apparatus shall be attached tothe valve outlet, as shown opposite.All openings -including but not limited to caps, drain holes, vents,and outlets – shall be closed.

A4 Test PressureFor a valve whose set pressure is greater than50 Psig, the leakage rate (in bubbles per minute)shall be determined with the test pressure at thevalve inlet held at 90% of the set pressure. For avalve set at 50 Psig or less, the test pressure shallbe held at 5 Psig less than the set pressure.

A5 Leakage TestBefore the leakage test, the set pressure shall bedemonstrated and all valve body joints and fittingsshould be checked with a suitable solution toensure that all joints are tight.

Before the bubble count, the test pressure shall beapplied for the following times:

Valve Size TimeUp to 2ins 1 min21⁄2ins to 4ins 2 min6ins and above 5 min

The valve shall then be observed for leakage for atleast 1 minute.

A6 Acceptance CriteriaFor a valve with a metal seat, the leakage rate inbubbles per minute shall not exceed theappropriate value in chart opposite. For a soft-seated valve, there shall be no leakage for 1 minute(0 bubbles per minute).

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Tube 5⁄16" o.d. x 0.035" wall

1⁄2"

Cover plate

Air receiver

Test apparatus forair seat tightness

API 527 Air Leakage Rates

110100

9080706050403020100

0 1000 2000 3000 4000 5000 6000

ORIFIC

E AREA

0.30

7in2

ORIFICE AREA 0.307in

2

Set Pressure Psig

Leak

age

Rat

e -

Bubb

les

per

min

ute

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Safeflo - Safety and Thermal Relief Valve

S A F E F L O F I G U R E N U M B E R I N G S YS T E M

OrificeArea in2

1 0.062**2 0.110**3 0.196**4 0.442**7 0.169*

Valve seriesB Gas vapourC LiquidD Gas and liquid

Inlet connection typeA BSP Tr male screwedB BSP female screwedC API male screwedD API female screwed1 ANSI 300/600 RF flange2 ANSI 900/1500 RF flange**3 ANSI 2500 RF flange**7 ANSI 150 RF flange**O Special**

Body material1 Carbon steel WCB2 Carbon steel WCB NACE3 Stainless steel CF8M NACE4 Stainless steel CF8MO Special**

Spring materialA Aluminium Coated CS2 Stainless steel 3166 Tungsten alloy9 Hastelloy B**Z Inconel X750O Special**

Trim - nozzle and disc material1 Stainless steel PH 17/42 Stainless steel 3164 Hastelloy B**5 Stainless steel 316 stellited**6 Monel 400**7 Stainless steel 304**O Special**

AccessoriesC Screwed capP Packed leverG Test gagF Ferrule (Government ring)S Special featureB Balanced piston*R Soft seat*

Outlet connection typeE BSP female screwedF API female screwed1 ANSI 150 RF flange2 ANSI 300 RF flange**O Special**

/ /

Different types:There are two different types, both are conventional designs.B Series - Safety and thermal relief valve, gas duty.C Series - Safety and thermal relief valve, liquid duty.D Series - Safety and thermal relief valve, gas and liquid duty.All are certified in accordance with ASME Code Section VIII.

Connection size1 1⁄2" x 1" orifice 1, 2 or 72 3⁄4" x 1" orifice 1, 2 or 73 1" x 11⁄2" orifice 34 11⁄2" x 2" orifice 4 – screwed only5 1" x 1" orifice 1, 2 or 7

*Available on D Series only.**Not available on D Series.

51

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Safeflo Design verification – the B Series(gas/vapour), C Series (liquid) and D Series(gas and liquid) have been developed onBirkett’s in-house, extensive mass flow testfacility.

Simplified maintenance – for the flangedversion, a slip on inlet flange makes it easier torealign into existing pipework after servicing.

Interchangeable parts – valves can easily bemodified from gas to liquid or liquid to gaswith the minimum number of parts.TheD Series is certified for both media withoutmodification.

Safe and reliable – proven dependabilityensures safe and reliable performance.

Cryogenic service – Birkett’s state-of-the-artclean room and vapour degreasing facilitiesensure compliance with the stringent demandsof cryogenic applications.

Material selection – a wide range ofmaterials are offered, including non-ferrous forlow temperature and oxygen service, andexotic alloys specified for the chemical andprocess industries.

1. Wide range of accessories – available tocomply with international codes and to suitsystem requirements.

2. High performance springs – Safetyrelief valve springs are specially designed toguarantee set point repeatability.

3. Guiding surfaces – The material selectionof guiding components, together with selfaligning disc pivot points, ensures correctalignment and no galling of guiding surfaces.

4. Trim – B/C Series valves have beendesigned with metal trim to give optimumperformance at higher pressures. D Seriesvalves have metal seats and the option ofsoft seats to give high performance sealing.

Balanced piston – Available on theD Series to counter the effects of variableback pressure.

1 Accessories

2 Highperformancesprings

3 Guidingsurfaces

4 Trim

5453

D S E R I E S T H E R M A L R E L I E F VA LV E S

SA

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O

SA

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3

13

34

33

12

32

22

11

1

6

9

31

5

76

4

85

2834

33

76

B / C S E R I E S T H E R M A L R E L I E F VA LV E S


1 Body SA 216-WCB CARB ST SA 351-CF8M ST ST3 Cap ASTM A108-1021 ASTM A479-316L4* Nozzle ASTM A479-316L ASTM A479-316L5* Disc ASTM A479-316L ASTM A479-316L6* Disc holder SA564 17/4 (33HRC) SA564 17/4 (33HRC)9 Guide AMS 5360B ST ST AMS 5360B ST ST11 Lower spring plate ASTM A479-431 ASTM A479-43112 Adjusting screw ASTM A479-410 ASTM A479-41013 Locking nut ASTM A479-316L ASTM A479-316L22* Spring C.S. ALUMINIUM COATED ASTM A313-31628* Cap gasket ST-706 ST-70631* Ball AISI 440C ST ST AISI 440C ST ST32 Upper spring plate ASTM A479 431 ASTM A479 43133 Data plate 321 ST ST 321 ST ST34 Hammer drive screw ELECTRO BRASSED CS ASTM A479-316L76 Capscrew ST ST BS6105 A2-70 ST ST BS6105 A2-7085 Flange SA 105 CARB ST SA 182-F316 ST ST

* Recommended spares.


1 Body SA 216-WCB CARB ST SA 351-CF8M ST ST3 Cap SA 216-WCB CARB ST SA 351-CF8M ST ST4* Nozzle ASTM A479-316L ASTM A479-316L5* Disc ASTM A479-316L ASTM A479-316L9 Guide NITRONIC 60 NITRONIC 6010 Spindle ASTM A479-431 ASTM A479-43112 Adjusting screw ASTM A479-410 ASTM A479-41013 Locking nut ASTM A479-316L ASTM A479-316L22* Spring C.S.ALUMINIUM COATED ASTM A313-31628* Cap gasket ST-706 ST-70630 Body gasket ST-706 ST-70631* Ball AISI 440C ST ST AISI 440C ST ST33 Data plate 321 ST ST 321 ST ST34 Hammer drive screw ELECTRO BRASSED CS. ASTM A479-316L75 Grub screw ASTM A479-316L ASTM A479-316L85 Inlet flange SA 105 CARB ST SA 182-F316 ST ST147 Flange nut SA564 17/4 (33HRC) SA564 17/4 (33HRC)188 Adjusting screw bush VIRGIN PTFE VIRGIN PTFE235 Spring end plate ASTM A479-431 ASTM A479-431

* Recommended spares.

3

33

34

33

34

188

12

13

28

235

235

22

1

10

9

5

31

30

75

4

85

147

56

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D I M E N S I O N S - S A F E F L O

B / C S E R I E S

D S E R I E S

Female screwed Male screwed Flanged

A

D

C

A

D

C

B

A

D

C

B

Note: A packedlever version andgagging facility arealso available.

1/2 x 1 Screwed 1 2.500 - 8.625 1.687 5000425 9 (4)Female 2 (64) (219) (43) 3600

3/4 x 1x 1 2.500 - 8.625 1.687 5000

425 9 (4)Female 2 (64) (219) (43) 3600

1 x 11 2.500 - 8.625 1.687 5000

425 9 (4)2 (64) (219) (43) 3600

1 x 11/2 33.250 - 13.750 2.375

5000 425 26 (12)(83) (349) (60)

11/2 x 2 43.250 - 13.750 2.375

2500 375 26 (12)(83) (349) (60)

1/2 x 1Screwed 1 2.562 0.750 9.375 1.687 3000

425 9 (4)Male 2 (65) (19) (238) (43) 1480

3/4 x 1x 1 2.562 0.750 9.375 1.687 5000

425 9 (4)Female 2 (65) (19) (238) (43) 3600

1 x 11 2.312 1.000 9.375 1.687 5000

425 9 (4)2 (59) (25) (238) (43) 3600

1 x 11/2 33.250 1.000 14.750 2.375

3000 425 26 (12)(83) (25) (375) (60)

11/2 x 2 43.125 1.125 14.875 2.375

2500 375 26 (12)(79) (29) (378) (60)3/4 x 1,

150# x 150# 1 + 24.625 1.000 10.250 3.750

285 285 17 (7.25)1 x 1 (117) (25) (260) (95)1/2 x 1, 3/4 x 1,

300/600# x 150# 1 + 24.625 1.375 10.250 3.750

1480 285†† 17 (7.25)1 x 1 (117) (35) (260) (95)1/2 x 1, 3/4 x 1,

900/1500# x 300# 1 + 24.625 1.187 10.375 3.750

3600 425 20 (9)1 x 1 (117) (46) (264) (95)

3/4 x 1, 1 x 1 2500# x 300#1 4.750 2.000 10.500 3.750 5000

425 20 (9)2 (121) (51) (267) (95) 3600

1 x 11/2 150# x 150# 35.625 1.000 16.750 5.500

285 285 40 (18)(143) (25) (425) (140)

1 x 11/2 300/600# x 150# 35.625 1.375 16.750 5.500

1480 285†† 40 (18)(143) (35) (425) (140)

1 x 11/2 900/1500# x 300# 35.625 1.812 16.750 5.500

3600 425 40 (18)(143) (46) (425) (140)

1 x 11/2 2500# x 300# 35.625 2.000 16.750 5.500

5000 425 40 (18)(143) (51) (425) (140)

Sizes (ins)inlet & outlet

Inlet & Outletconnection

OrificeNo.

Dimensions ins (mm)Max pressure upto

100°F (Psig)A B C* D Inlet Outlet

Weightlbs (kg)

*If a gag screw is fitted, add 2 ins (51mm) to dimension C for orifice nos. 1 & 2 only. ††425 Psig with 300# outlet*If a packed lever is fitted, add 13⁄4 ins (44mm) to dimension C for orifice nos. 1 & 2 only.

†If a packed lever is fitted, add 1.062 ins (27mm) to dimension C for orifice 7 only.†If a gag screw is fitted, add 0.395 ins (10mm) to dimension C for orifice 7 only.†If a balanced piston is fitted, add 2.125 ins (54mm) to dimension C for orifice 7 only.†If a gagged balanced piston is fitted, add 2.520 ins (64mm) to dimension C for orifice 7 only.

1/2 x 1 Screwed 7 1.732 - 7.440 2.165740 285 9 (4)

3/4 x 1 Female x Female (44) (189) (55)

1 x 1 Screwed7

1.687 0.750 8.230 2.165740 285 9 (4)Male x Female (43) (19) (209) (55)

3/4 x 1ANSI 300# x 150# 7

4.610 1.625 10.315 3.750740 285 14 (6.5)1 x 1 (117) (41) (262) (95)

Sizes (ins)inlet & outlet

Inlet & Outlet connection

OrificeNo.

Dimensions ins (mm)Max pressure upto

100°F (Psig)A B C† D Inlet Outlet

Weightlbs (kg)

Orifice sizes:refer to sizing section, page 84.

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Packed lever

The design of the packed lever assembly ensures thatleakage does not occur when the valve is open orwhen back pressure is present.

Open lever design is not available on Safeflo valves.

Balanced piston

This option is only available on the D Series valves.It is designed to overcome the effects of variableback pressure.

Test gag

The test gag is used to prevent thesafety valve from lifting. This ismainly used when carrying out ahydrostatic test on the system,during commissioning.

The test gag must never be left inthe valve. The sealing plug shouldbe fitted at all other times, allowingthe valve to operate freely.

Pressure adjustment: refer to page 47.

Cold differential test pressure: refer to page 47.

Seat tightness/Seat leakage testing: refer to page 49/50.

Minimum pressure setting: B Series, normal attitude 10 Psig.C Series, normal attitude 15 Psig.D Series, normal attitude 5 Psig.

Lower pressures are not available by inverting the valve.

Gag Screw

Sealing Plug

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F E AT U R E S A N D B E N E F I T S O F S A F E S E T

Close System Operating PressureThe system operating pressure can be much closerto the set pressure on a pilot operated valve thanwith a standard spring loaded safety relief valve.System pressures in the region of 95 to 98% of setpressure are often accommodated.

Tolerates High Inlet Pressure LossHigh inlet pressure losses due to difficult inletpiping systems can be accommodated by remotesensing the pilots, hence trouble free operation canbe assured.

Unique Modulating PilotOur unique design on liquid duty eliminatesvibration and assures trouble free operation.

1. Close Differential Pressure Setting – Popacting pilot valves are quick acting and hencethere is no delay between the pilot and the mainvalve opening pressures. Modulating valvesinherently have a delay, this can typically be ashigh as 6% on other manufacturer’s designs,Safeset is a nominal 2%. This ensures the pilot isnot leaking when the system pressure is closeto the set pressure.

2. Close Blowdown and OverpressureTolerance – Pop action pilots can be adjustedto give zero overpressure and blowdownstypically less than 3% of set pressure.

3. Non Flowing Pilot – Safeset pilots are of thenon flowing design. The risk of freezing due topressure drops in the flowing medium isremoved. Additionally, dirt particles are nottransported to the pilot as the medium is static.This improves life in service and ensures troublefree operation.

4. Integral Pilot Filter – Safeset pilots are fittedwith integral filters which are designed in such amanner that the valve will still operate shouldthe filter block.

5. Stainless Steel – Safeset pilots, domes, tubesand fittings, pistons and nozzles are made fromstainless steel as a minimum, i.e. all processwetted parts. This reduces the risk of oxidescontaminating seals and hence prolongs their lifein service.

6. Adjustable Orifice Areas – The standardrange of single outlet main valves consists of 8body sizes, which by simple adjustmentaccommodates all 22 standard orifice sizes.Thisallows for easy adjustment should serviceconditions dictate a change in required orificearea.

7. Full Lift Capability – Pilot valves will maintainfull lift against high levels of back pressure.Unlike spring loaded valves, which would needeither differential setting or the addition ofbalanced bellows.

8. Soft Seat – Safeset pilots and main valves aresoft seated to give optimum leak tightness.Materials are available for a wide range ofduties. Maintenance is simplified as seat lappingis reduced.

9. Enhanced Seat Tightness – The main valve ispiston operated.The piston area is in excess of30% larger than the seat bore area.This ensuresthe seat closing force is always at least 30%greater than the seat opening force for allpressures, right up to the set point.Thisproduces more effective seat tightness, reducingthe possibility of seat leakage.

A spring loaded valve will have maximum seatclamping force when there is no systempressure. As the system pressure approachesthe set point, the upward acting valve openingforce approaches the closing force generated bythe spring, hence the clamping force approacheszero and seat leakage may occur. A pilot valvewith a 30% differential piston design willmaintain a 30% seat clamping force right up tothe set point, ensuring maximum seat tightness.

Seat clamping = Valve closing forceforce – Valve opening force

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Safeset - Pilot Operated Safety Relief Valve

14 Two part piston assembly

15 State-of-the-art piston seals

1 Close differentialpressure setting

2 Close blowdownand overpressuretolerance

3 Non-flowingpilots

4 Integralfailsafepilot filter

5 All stainlesssteel pilots,dome, tubesand fittings

6 Adjustableorifice areas

7 Full liftcapability

8 Soft seat

9 Enhancedseattightness

10 Unique fullnozzle design

11 API 526compliant

12 Integral sensingof pilot

13 Dual outlet option

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S A F E S E T - M O D E O F O P E R AT I O N

Safeset consists of a separate pilot valveconnected to a main valve via a sensing pipe.Thispipe senses the inlet pressure within the main valvenozzle and provides the pressure signal to thepilot.

Pilot valve

The pilot valve controls the discharge offluid through the main valve byresponding accurately to the systempressure. All Bailey Birkett pilots arenon flowing designs, which means thereis an absence of system flow throughthe pilot during the relief cycle.

The benefits of non flowing designsare that freezing of moisture-containing fluid and the carrying ofparticulate matter into the pilot areminimised, ensuring correct valveperformance.

MAINVALVE

PILOTVALVE

Main ValveThe main valve conforms to the latest version ofAPI 526 Pressure/Temperature ratings and face toface dimensions. It has 22 orifice variants in just 8inlet x outlet body sizes. Safeset is a differentialpiston operated design, the opening is controlledby the pilot valve.

Pop (Type A) – Controls the main valve in a rapidmanner, it is either open or closed. Specifically forgas applications.

Modulating (Types B+D) – The main valve isopened in a controlled manner, the over pressureis constantly monitored and the opening of themain valve is proportionate to the overpressure.Type B for liquid duty, type D for gas duty.

B A S I C O P E R AT I O N O F S A F E S E T

T H R E E D E S I G N S O F P I L OT VA LV E

Simply, the pilot valve is a very accurate spring-loaded safety valve, with two seats. At low systempressures, pressure from the system is fed from theinlet nozzle, through the sense line, past the lowerpilot seat and into the main valve dome.The domearea is in excess of 30% larger than the seat borearea.This differential of areas ensures that the mainvalve remains closed.When the system pressure

Pop/Modulating (Types C + E) – Designedspecifically for duties with varied upset flowconditions. Gradual rises in system pressure pastthe set point will see the main valve have a shortpop & then modulating action.A rapid rise,however, will see the main valve respond with apop action to the full open position.

Type C for liquid duty,Type E for gas duty.

reaches the set point of the pilot, the lower pilotseat closes and the upper pilot seat opens,releasing the dome pressure to the atmosphere.With no pressure above the piston, the main valveopens.The reverse of this sequence of eventsoccurs when system pressure falls and once againthe main valve dome will be fed with systempressure, which in turn closes the main valve.

10. Unique Full Nozzle Design – The nozzle isa patented push-in design, held in position witha locking ring. Being of the full nozzle design, itreduces mechanical and thermal stresses at theseat, reduces inlet pressure losses, increasesthe discharge co-efficient and allows for lowerspecification body materials on corrosiveduties.

11.API 526 Compliant – Fully conforms to thelatest edition of API526 for pressure/temperature ratings and over flangedimensions for pilot valves.

12. Integral Sensing – Safeset pilots are sensedfrom the nozzle, giving a compact design andaccurate pressure sense from within the flowstream. Remote sensing for difficult inlet pipingsystems is recommended.

13. Dual Outlet Option – The 8ins valve is alsoavailable with a dual outlet (see below).

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14.Two Part Piston-Disc Assembly – This givesa reduced guiding geometry, keeping the size ofthe components within the body bowl to aminimum, thus increasing the effectivedischarge area through the valve outlet.

15. State of the Art Piston Seals and BearingRings – Reduce friction and galling ofmaterials at the guide and pistons surfaces –essential for modulating pilots.

D UA L O U T L E T / F U L L B O R E P I L OT VA LV E

This valve is suitable for extremely highcapacity duties. It achieves maximum dischargecapacities by having a full bore 8 inch inletwith an available discharge area of 44.178sq.in. and two opposing 10 inch outlets, whichcan assist with reaction force problems.

Available with all pilot types A, B, C, D and E.

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P O P AC T I O N - T Y P E A P I L OT

Pilot operation

With pop action pilot operation, the main valve iseither in the fully open or shut position. Theoperation is characterised by a distinct rapid “pop”action, which is evident at the opening of the mainvalve, followed by a positive re-seat action whenthe main valve closes.

This graph demonstrates pop action. When setpressure is reached, the pilot valve opens rapidly;this action de-pressurises the dome volume veryquickly and the main valve opens. This is shown bythe vertical (rising) line on the graph, illustratingthat the main valve achieves its design lift at setpressure.

The re-seating characteristic is equally positive:when the system pressure has fallen to the pre-setpilot re-seat pressure, the pilot drain seat closesrapidly. This action allows the dome to be re-pressurised very quickly, thereby closing the mainvalve completely. This is shown on the graph bythe vertical (falling) line.

TO ANDFROM MAINVALVE DOME

UPPERDRAINSEAT

LOWERFEEDINGSEAT

FILTER

SETTINGSPRING

Pilot construction

The pilot is essentially a spring loadedsafety valve with blow-down adjustmentwhich, during its operation, positionsitself on one of two seats. The upperdrain seat is used to determine pilot setpressure, the lower feeding seatdetermines pilot blow-down.

The valve disc is held on the soft upperdrain seat by the setting spring, whichalso determines the pilot set pressure.This valve disc is connected via a spindleto the lower feeding seat ball, whichcontrols the system flow into the domeand which also controls the pilot blow-down.

The valve disc and lower feeding seat ballmove together; this action opens andcloses each respective seat, therebyallowing the pilot to control theoperation of the main valve during therelieving cycle.

The re-seat pressure of the Type A pilot valve isadjustable externally, independently of the setpressure adjustment.

S TAG E S O F O P E R AT I O N - T Y P E A P I L OT

Stage 1System pressure below thepilot set pressure, domepressurised, main valve closed.

Stage 2System pressure equal toset pressure, drain seatopens, dome de-pressurises,main valve fully lifts with nooverpressure.

Stage 3System pressure equal toor greater than setpressure, dome pressureis atmospheric, main valveis fully open.

Stage 5System pressurebelow the pilot setpressure, domepressurised, mainvalve closed andready for next upsetcondition.

Stage 4System pressure falls toequal the re-seat pressure,drain seat closes, feedingseat opens, dome ispressurised, main valvecloses.

Key Points – Pilot Type A� Pilot set pressure = Main valve set pressure.� Main valve fully open at 0% overpressure.� The pilot is non flowing.� Adjustable blow-down feature.� Integral fail safe filter fitted.� Gas duty only.

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Pilot Operation

The action of the main valve may be characterisedas “modulating”. In order to achieve this the pilotaccurately controls the pressure in the main valvedome which positions the main valve disc tomatch the system upset flow condition; this willthen control the system pressure.

Effective pilot operation requires a small overpres-sure above the set pressure, to achieve full designlift of the main valve and a small pressure drop tore-seat the main valve.

A typical modulating performance is shown in thegraph below. The overpressure as a percentage ofset pressure will vary with the system flowrequirement; this means that an infinite number ofrelieving cycles can occur within the limits shown.The valve lift will, however, always be in proportionto the rise in system pressure, ensuring a safestable relief cycle.

M O D U L AT I N G AC T I O N - T Y P E S B A N D D

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M O D U L AT I N G AC T I O N - T Y P E S B A N D D

Pilot construction

Modulating pilots are essentially diaphragm-operated safety valves with a feedback piston forfine control of the pressure in the dome.

When the set pressure is reached the main valveopens in proportion to the system pressure rise.This is achieved by the pilot controlling the domepressure. The main valve will maintain a liftnecessary to discharge the system flow. As thesystem pressure increases, the main valve lift willchange to accommodate the new flow condition.As the system pressure falls, the main valve willbegin to close, finally closing at a pressure justbelow the set pressure.

The diaphragm senses the system pressure andthe feedback piston senses the dome pressure.Between them they accurately feed pressure tothe dome to close the main valve or releasepressure from the dome to the drain to open themain valve.

Fail safe operation is assured on account of theintegral filter which protects the feeding and drainseats.

When used on liquid or mixed phase duty, thetype B Pilot is connected to the main valve nozzleentry with two sensing pipes at 180 deg. to eachother. This configuration ensures that pressure issensed independently by the diaphragm and thedome. It is essential for fail safe operation of thepilot that the dome and diaphragm chambers arenot connected together. With these pilots thereis no flow into or out of the diaphragm chamberand therefore the entry of particulate matter intothe diaphragm sensing line is greatly reduced. Thisprinciple also ensures that any pressure spikes occurring within the dome volume during mainvalve operation is not sensed by the diaphragm.

The pilot has been specially designed toincorporate an anti pulsation device in thediaphragm chamber, this gives further protectionagainst pressure surges in the inlet pipework.

SETTINGSPRING

DOME

DOME

FILTER

Type D Pilot - Gas Duty only(Single feeding line from nozzle)

Type B Pilot – Liquid and Mixed Phase Duties(Two feeding lines from nozzle)

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STAGE 4System pressure above set pressure

As the system pressure increases above the setpressure, modulation occurs with the main valveopening an amount sufficient to maintain systemflow rate. This is brought about by the increasedsystem pressure acting against the pilot diaphragmto re-open the drain seat. The dome pressure isreduced further, allowing the main valve to open.The reduced dome pressure now acting on thefeedback piston produces a lower upward forceand the adjusting spring closes the drain seat.

The above actions cycle in very small incrementsand hence give the modulating effect.

STAGE 5Main valve fully open

When the system pressure reaches 105% of theset pressure the main valve will be fully open.

STAGE 6

Main valve closes

When the system upset condition has ended, thesystem pressure will begin to fall. The reducedsystem pressure acting on the pilot diaphragm willcause the feeding seat to re-open. This willincrease the dome pressure and the main valve willbegin to close. The feeding seat will close as thedome pressure increases due to the feedbackpiston effect. This cycle will repeat as the systempressure is further reduced.The main valve willclose with a progressive action.When the systempressure reaches 97% of set pressure the mainvalve will be closed.

Key points – Pilot Types B and D

� Pilot set pressure is when the drain seatfirst opens.

� Main valve discharge maintains the systempressure at its respective flow condition,thereby achieving fully modulating action.

� The pilot valve is firmly closed when themain valve closes.

� Integral fail safe filter fitted.

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S TAG E S O F O P E R AT I O N - T Y P E S B A N D D

Type B & D Pilots are fully modulating. The B typeis intended for use with liquids and mixed phasefluids and the D type is intended for use withgases. Both types are non flowing designs.

STAGE 1System pressure below 96% of set pressure

The feeding seat remains open with the drain seatclosed. This maintains equal pressures in thedome and the system. The main valve is closed,held tightly against the nozzle.

STAGE 2System pressure approaches set pressure

When the system pressure reaches 96% of the setpressure the feeding seat closes. The drain seatremains closed and the main valve is closed.

The pressure in the dome is now controlled bythe inlet system pressure acting against the pilotdiaphragm and the dome pressure acting on thefeed back piston. The combination of these twoforces controls the opening of the drain seat,thereby controlling the dome pressure and hencethe main valve lift.

When the system pressure rises to 98% of setpressure the drain seat will open and discharge asmall volume of fluid from the dome. At no timeis the drain seat continually flowing. It drains inshort bursts.

STAGE 3System pressure reaches set pressure

As the system pressure gradually rises a further2% up to the set pressure, the dome pressuregradually falls approximately 30%. Due to thedifferential size, top and bottom of the piston, themain valve opening and closing forces are now inequilibrium.

P

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S TAG E S O F O P E R AT I O N - T Y P E S C A N D E

These types of pilots are characterised by popaction followed by a modulating action. Type C is intended for use with liquids and mixed phasefluids. Type E is intended for use with gases. Bothtypes are non flowing and the re-seat pressure isfixed and non adjustable.

STAGE 1

System pressure below 98% of pilot setpressure

The feeding seat remains open and the drain seat isclosed. This maintains equal pressures in the domeand the system. The main valve is closed.

STAGE 2

System pressure approaches set pressure

When the system pressure reaches 98% of setpressure the feeding seat closes. The drain seatremains closed, and the main valve is closed.

STAGE 3

System pressure reaches set pressure

As the system pressure gradually rises a further 2%up to the set pressure, the dome pressuregradually falls approximately 30%. Due to thedifferential size, top and bottom of the piston, themain valve opening and closing forces are now inequilibrium. On achieving the set pressure the mainvalve opens with a sharp pop action.

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P O P / M O D U L AT I N G AC T I O N - T Y P E S C A N D E

Pilot construction

The construction of the pilot is identical to types Band D but without the feedback piston which isreplaced with a sealed spindle. This gives a quitedistinct operating characteristic to the main valve.

The main valve opens with a short pop followed bya modulating action. The pilot valve requires asmall overpressure to lift the main valve to its fulllift position.

The pilots are connected to the main valve nozzleentry using sensing pipes identical to those of typeB & D pilots. Two sensing pipes are used on the Cpilot for liquid and mixed phase duty, ensuring failsafe operation by independent sensing of thediaphragm and dome chambers.

SETTINGSPRING

SPINDLE

DOME

DOME

FILTER

Type E – Gas Duty only(Single feed line from nozzle)

Type C Pilot – Liquid and Mixed Phase Duties(Two feeding lines from nozzle)

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Key points – Pilot Types C and E

� Pilot set pressure is when the drain seatfirst opens.

� Pilot set pressure = Main valve set pressure.

� Main valve is fully open with < 3% overpressure.

� Main valve lifting action is an initial shortpop, suitable where faster response isrequired on liquid service than would beachieved with a fully modulating pilot.

� The pilot valve is firmly closed when themain valve re-seats.

� Integral fail safe filter fitted.

STAGE 4

Main valve fully open

After the initial pop of the main valve, a small risein system pressure is necessary to vent the dome completely and open the main valve fully. This isless than 3%, and is achieved with a modulatingaction.

STAGE 5

Main valve closing

When the system pressure falls under the influ-ence of the main valve discharge, the drain seatcloses and the feeding seat starts to open. Thisopens the dome line to the main valve piston.Pressure is then fed back into the dome to startthe main valve closing cycle.

STAGE 6

Main valve closed

After the relieving cycle has been completed, themain valve closes tightly against the nozzle. Thiswill occur at approximately 5% below the set pres-sure. The drain seat is firmly closed and thefeeding seat is in its fully open position. Pressure isnow equalised throughout the system.

L I Q U I D O R D UA L P H A S E P I P I N G A R R A N G E M E N T

Pilots on liquid or dual phase duties require twoinlet sense lines from the inlet nozzle.This is toensure fail safe operation.

Type BLiquid or Dual Phase Modulating Action

Type CLiquid or Dual Phase Pop/Modulating Action

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M AT E R I A L S O F C O N S T RU C T I O N - M A I N VA LV E

BODY MATERIAL CARBON STEEL STAINLESS STEEL

Item Description † -29 to +260 ºC -46 to +260 ºC -46 to +260 ºC

1 Body SA 216 WCB SA 352 LCB SA 351 CF8M2 Nozzle St. St. 316 St. St. 316 St. St. 3163 Guide St. St. 17/4 St. St. 17/4 St. St. 17/44 Disc holder St. St. 316 St. St. 316 St. St. 3165 Disc insert Viton * Viton * Viton *6 Piston St. St. 316 St. St. 316 St. St. 3167 Locknut St. St. 316 St. St. 316 St. St. 3168 Lift stop St. St. 316 St. St. 316 St. St. 3169 Cover St. St. 316 St. St.316 St. St. 31610 Retaining plate St. St. 316 St. St. 316 St. St. 31611 Disc holder seal Viton * Viton * Viton *12 Piston seal Viton * Viton * Viton *13&25 Guide rings Carbon/PTFE Carbon/PTFE Carbon/PTFE14 Body stud A193/B7 A193/B8T A193/B8T15 Body nut A194/2H A194/8T A194/8T16 Lock ring St. St. 316 St. St. 316 St. St. 31619 Spring St. St. 316 St. St. 316 St. St. 31620 Body gasket Carbon fibre Carbon fibre Carbon fibre *21 Guide seal Viton * Viton * Viton *22 Nozzle seal Viton * Viton * Viton *23 Retaining plate screw Viton * Viton * Viton*24 Counter sunk screw St. St. 316 St. St. 316 St. St. 31627 Fittings St. St. 316 St. St. 316 St. St. 31632 Tubes St. St. 316 St. St. 316 St. St. 316

Note:*Soft goods materials listed above are standard. For a full listing to cover the temperature ranges of the body materials listedabove, it is necessary to refer to the seals, gaskets, selection table on the previous page.†Maximum temperature is limited by the seal material.Alternative materials and accessories are available, for NACE, high temperatures and cryogenic applications.

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T E C H N I C A L S P E C I F I C AT I O N - P I L OT VA LV E

M AT E R I A L O F C O N S T RU C T I O N – P I L OT VA LV E

Type A pilot must have the exhaust vent open to atmosphere or piped to a safe area. Types B, C, D and Epilots may have either atmospheric drain or have their exhaust vents connected into the main valve bodydischarge port with back pressures.

Valve type A B C D E

Pilot action Pop Mod Pop/Mod Mod Pop/Mod

Fluid Gas Liquid Liquid Gas GasDual Phase Dual Phase

Overpressure 0% 5% <3% 5% <3%

Blow-down 1-10%* <3% 5% <3% 5%Adjustable Fixed Fixed Fixed Fixed

Pilot/main valve set pressure differential0% 2% 0% 2% 0%

Max back pressure Built up and Superimposed70% 70% 70% 70% 70%

Back pressures in excess of these limits can be accommodated - consult factory

Pressure (Psig) 26-6170 43-1480 29-4350 43-1480 29-4350range (Barg) 1.8-425.5 3-102 2-300 2-102 2-300

High pressure pilots are available - consult factory

Temp. range (deg F) -50 to 500 -50 to 500 -50 to 500 -50 to 500 -50 to 500(deg C) -46 to 260 -46 to 260 -46 to 260 -46 to 260 -46 to 260

Accessories are available for cryogenic and high temperature applications - consult factory

*Unless otherwise required or specified, the type A Pilot will be factory set for 5% blow down.

Pilot Type Type A Types B and D Types C and E

Body ST.ST 304 ST.ST 316 ST.ST 316

Bonnet ST.ST 316 ST.ST 316 ST.ST 316

Spring ST.ST 302 Carbon ST. Plated Carbon ST. Plated

Trim ST.ST 316 ST.ST 316 ST.ST 316

Seat Seals* Viton Viton Viton

Note:Safeset pilot valves are available for NACE applications.*Soft goods materials are dependant upon temperature and fluid.*Options are available to cover the main valve body temperature ranges. See table below.

Main Valve Seat & Piston Seals Viton Buna - N Filled/PTFETemp (deg C) -18/+205 -46/+120 -46/+260

Static Seals Viton TFE(AFLAS) Buna - N Chemraz KalrezTemp (deg C) -18/+205 0/+200 -46/+120 -30/+230 -15/+260

Gaskets Carbon Fibre Laminated GraphiteTemp (deg C) -46/+260 -46/+260

Seals/Gaskets

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Back flow preventerHigh back pressures may exist in the outlet forvarious reasons such as common disposalsystems. If this backpressure can be more thanthe inlet system operating pressure, the mainvalve could lift allowing reverse flow from theoutlet to inlet system.

A back flow preventer is a two-way check valve,which is fitted into the dome line. It allows thehighest pressure from either the inlet system oroutlet system to enter the dome, ensuring themain valve remains closed and prevents thepossibility of reverse flow. Must not be used if theback pressure is more than 50% of the setpressure.

External supply filterThis unit protects the pilot valve when workingunder “dirty” flow stream conditions.All Safesetpilots are fitted with integral filters as standard;however, under conditions where there is likely tobe large amounts of particulate matter in the flowstream, a supply filter should be used.This unit isfitted into the pilot sensing pipe, upstream of thepilot, and is suitable for gas and liquid duty. It isremoved easily for maintenance.

Heating or cooling coilsHigh or low temperature duties may require theaddition of coils to act as heat exchangers toeither warm or cool the medium before it entersthe pilot valve or main valve dome.This ensuresthat extremeties of temperature do not affect theoperation of the safety valve.


Remote pressure sensing

Many codes and standards restrict the inletpipework pressure loss to 3% of the safety valveset pressure. There are occasions however, whenthe pipework loss is greater than this. In theseinstances the safety valve should always beconnected for remote sensing.The valve is normally supplied with integral sensing; this meansthat the pilot senses pressure at the main valvenozzle entry. Under conditions of excessivesystem pressure loss, the valve, under flowingconditions, may cycle open and closed. This is dueto the pilot sensing a reduced (artificial) pressure.

In order to overcome this problem the valveshould be sensed remotely. The pilot in this caseshould have its inlet connected directly to thepressure source where the system pressure isstable and not flowing. The main valve nozzle willnot contain a sensing tapping in this case.

Excessive system pressure losses will also reducethe flow rate through the valve. This will be in proportion to the absolute system pressure andmust be taken into account when sizing the valve.

Remote sensing will ensure that the pilot operatedsafety valve operates without cycling or chatterwhen high inlet pressure losses are encountered.

Remote Pressure Sensing

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Back FlowPreventer

ExteriorSupply Filter

Field TestConnector

Remote Pressure Sensing

Heating orCooling Coils

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S A F E S E T P I L OT F I G U R E N U M B E R I N G S YS T E M

Inlet Diameter1 - 8"

Pilot descriptionA pop action, gasB modulating, liquidC pop/modulating, liquidD modulating, gasE pop/modulating, gas

Flange type1 ANSI RF x RF2 ANSI RTJ x RFO Special

ANSI flange rating1 150 x 1502 300 x 1503 600 x 1505 900 x 3007 1500 x 3008 2500 x 300A 600 x 300B 1500 x 600C 2500 x 600O Special

/

Orifice designation D-TX = 8" x 10" x 10" full bore

Outlet diameter 2" - 10"

AccessoriesA remote pressure sensingB back flow preventerC cooling/heating coilsD screwed capE external filterG test gagP packed leverT field test connectorU remote unloaderS special

Pressure range Psig (Barg)Range Type A Type B & D Type C & E

1 26 - 101.5 43 - 520 29 - 520(1.8 - 7) (3 - 36) (2 - 36)

2 >101.5 - 2175 >520 - 1480 >520 - 1480(>7 - 150) (>36 - 102) (>36 - 102)

3 >2175 - 6170 – >1480 - 4350(>150 - 425.5) – (>102 - 300)

These are min/max pressures of the pilot.Several springs are required to cover these ranges

Main valve spring material2 St steel 316Z Inconel X750 (NACE)O Special

Main valve trim2 316 disc/316 nozzle/Viton4 316 disc/316 nozzle/Buna N9 316 disc/316 nozzle/PTFEO Special

Main valve body code1 Carbon steel SA 216-WCB2 Carbon Steel SA 216-WCB (NACE)3 St steel SA 351-CF8M (NACE)4 St steel SA 351-CF8MO Special S

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Remote unloader

This device enables the main valve to be openedremotely. It is a three way spool valve which canbe operated electronically or pneumatically.

The valve is mounted into the dome line andallows a free flow from the pilot into the dome.When remote operation is required, a signal (pneu-matic or electrical) opens the exhaust vent of thespool valve and vents the dome, allowing the mainvalve to open.

The valve will normally be supplied mounted ontothe main valve with the dome connected directlyto the pilot.

When the spool valve is energised the dome willvent directly to atmosphere.

Remote Unloader

Field test connectorThis provides verification of set pressure settingduring normal system operation.The field testconnector is a two way check valve which is fittedinto the sensing pipe and is an integral part of thepilot operated valve system. If this facility isrequired, it must be specified on the valve order.An external pressure supply needs to be connectedto the check valve via an isolating valve andpressure gauge.The external pressure should beadmitted slowly through the supply isolating valve.When the supply pressure is greater than thesystem pressure the check valve delivery seat willopen and the system seat will close.Pressure can now be applied to the pilot anddome.When set pressure is reached the pilot willopen. N.B. Pop action pilots will ‘pop’ open; this isthe main valve set pressure. Modulating pilots willstart to vent from their drain seat; this will occur at2% below the main valve set pressure.Thenameplate should be referred to in order to obtainthe main valve set pressure.The main valve may open briefly with pop actionpilots.

OthersSimilar to the spring loaded safety relief valves (seepage 15), pilot valves can be fitted with:

� Packed lift levers.� Ferrules (government rings).� Test gags.

Available options

� Dual and triple pilot assemblies.� Heated or unheated control cabinets.� Dual outlet/full bore design.

Size Orifice Rating A (ins) D (ins) B (ins) C (ins) C (ins) C (ins) Weight(ins) Type A Type Remote lbs (kg)

B,C,D,E pilot

1 x 2 D, E, F 150x150 4.13 4.50 1.69 14.00 17.00 9.00 42 (19)300x150 4.38 4.50 1.69 14.00 17.00 9.00 45 (20.5)600x150 4.38 4.50 1.69 14.00 17.00 9.00 45 (20.5)900x300 4.94 4.75 2.25 16.00 18.00 11.50 53 (24)1500x300 4.94 4.75 2.25 16.00 18.00 11.50 53 (24)2500x300 4.94 4.75 2.25 16.00 18.00 11.50 53 (24)

1.5 x 2 D, E, F 150x150 4.88 4.75 1.69 14.50 18.00 9.50 46 (21)300x150 4.88 4.75 1.69 14.50 18.00 9.50 49 (22)600x150 4.88 4.75 1.69 14.50 18.00 9.50 49 (22)900x300 5.88 5.50 2.63 17.00 19.00 12.50 57 (26)1500x300 5.88 5.50 2.63 17.00 19.00 12.50 57 (26)2500x300 5.88 5.50 2.63 17.00 19.00 12.50 57 (26)

1.5 x 3 G, H 150x150 5.13 4.88 1.69 15.00 18.00 10.25 55 (25)300x150 5.13 4.88 1.69 15.00 18.00 10.25 62 (28)600x150 5.13 4.88 1.69 15.00 18.00 10.25 62 (28)900x300 6.38 6.75 2.62 18.25 22.00 13.50 79 (36)1500x300 6.38 6.75 2.62 18.25 22.00 13.50 79 (36)2500x300 6.38 6.75 2.62 18.25 22.00 13.50 79 (36)

2 x 3 G, H, J 150x150 5.38 4.88 1.81 15.25 19.00 10.50 55 (25)300x150 5.38 4.88 1.81 15.25 19.00 10.50 60 (27)600x150 5.38 4.88 1.81 15.25 19.00 10.50 64 (29)900x300 6.56 6.75 2.44 19.25 19.25 14.50 93 (42)1500x300 6.56 6.75 2.44 19.25 19.25 14.50 93 (42)1500x600 6.56 6.75 2.44 19.25 19.25 14.50 93 (42)2500x300 7.00 6.75 2.88 19.25 19.25 15.00 104 (47)2500x600 7.00 6.75 2.88 19.25 19.25 15.00 104 (47)

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D I M E N S I O N S

Notes:• Certified dimensions available on request.

• Dimensions A and B are for RF inlet, sensedintegrally and remotely.

• Dimensions A and B are for RTJ inlet, sensedremotely.

• Add 1/2" to dimensions A and B for RTJ inlets1" to 3" when sensed integrally.

• Add 3/4" to dimensions A and B for RTJ inlets4" to 6" when sensed integrally.

• Add 1" to dimensions A and B for RTJ inlet 8"when sensed integrally.

• Height may vary.

• Weight is approximate for Type A pilot. ForTypes B,C,D & E pilots add approx. 11kg.

• Cap withdrawal 40mm (1.6").

• Additional filter 3.5kg.

Size Orifice Rating A (ins) D (ins) B (ins) C (ins) C (ins) C (ins) Weight(ins) Type A Type Remote lbs (kg)

B,C,D,E pilot

3 x 4 J, K, L 150x150 6.13 6.38 2.00 17.00 20.00 12.00 137 (62)300x150 6.13 6.38 2.00 17.00 20.00 12.00 137 (62)600x150 6.33 6.38 2.25 17.25 22.00 12.25 154 (70)600x300 7.50 7.13 3.00 20.25 23.00 15.50 183 (83)900x300 7.50 7.13 3.00 20.25 23.00 15.50 205 (93)1500x300 7.50 7.13 3.00 20.25 23.00 15.50 214 (97)1500x600 7.50 7.63 3.00 20.25 23.00 15.50 227 (103)

4 x 6 L, M, 150x150 7.75 8.25 2.31 20.75 23.00 15.50 225 (102)N, P 300x150 7.75 8.25 2.31 20.75 23.00 15.50 225 (102)

600x150 7.75 8.25 2.31 20.75 23.00 15.50 225 (102)600x300 9.81 9.19 3.38 25.00 26.00 19.75 370 (168)900x300 9.81 9.19 3.38 25.00 26.00 19.75 390 (177)1500x300 9.81 9.19 3.38 25.00 26.00 19.75 401 (182)1500x600 9.81 10.38 3.57 25.25 26.00 20.25 456 (207)

6 x 8 Q, R 150x150 9.44 9.50 2.31 25.50 26.00 20.50 403 (183)300x150 9.44 9.50 2.31 25.50 26.00 20.50 408 (185)600x150 9.69 9.50 2.75 25.50 26.00 20.75 419 (190)600x300 9.69 10.44 2.75 26.00 26.00 21.00 556 (252)

8 x 10 S,T 150x150 10.88 11.00 2.69 29.00 29.00 24.50 595 (270)300x150 10.88 11.00 2.69 29.00 29.00 24.50 661 (300)600x150 11.69 11.00 3.25 29.75 29.00 24.25 728 (330)600x300 11.69 12.00 3.25 30.25 29.00 25.75 948 (430)

8x10x10 X 150x150 10.88 11.00 1.75 31.75 31.75 31.00 959 (435)300x150 10.88 11.00 1.75 31.75 31.75 31.00 959 (435)

SINGLE OUTLET

DUAL OUTLET

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260

-29-46-50

260

-29-46-50

Graph 1.0ANSI Class 150,300,600 Inlet Flange Valves

Graph 2.0ANSI Class 900,1500,2500 Inlet Flange Valves

Set Pressure (Barg)

Set Pressure (Barg)

F L A N G E P R E S S U R E / T E M P E R AT U R E L I M I T S

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Notes:• Outlet pressure limits for temperature above 100°F to conform to ANSI/ASME B16.34.

• Pressure ratings given are for carbon steel bodies at -20°F to 100°F. Austenitic stainless steel and othermaterials suitable for the service may be used within the code limits for pressure and temperature.

• API Standard 526 specifies lower allowable pressures for service temperatures above and below theranges given in these charts, for both carbon and stainless steel bodies.

Maximum Operating Pressures to API 526

Size Orifice ANSI Maximum (ins) Flange Pressure

(Psig)Inlet Outlet Inlet Outlet

1x2 D, E, F 150 150 285 285300 150 740 285600 150 1480 285900 300 2220 7401500 300 3705 7402500 300 6170 740

11/2x2 D, E, F 150 150 285 285300 150 740 285600 150 1480 285900 300 2220 7401500 300 3705 7402500 300 6170 740

11/2x3 G, H 150 150 285 285300 150 740 285600 150 1480 285900 300 2220 7401500 300 3705 7402500 300 6170 740

2x3 G, H 150 150 285 285300 150 740 285600 150 1480 285900 300 2220 7401500 300 3705 7402500 300 6170 740

2x3 J 150 150 285 285300 150 740 285600 150 1480 285900 300 2220 7401500 300 3650 7401500 600 3705 14802500 300 3650 7402500 600 6170 1480

3x4 J, K 150 150 285 285300 150 740 285600 150 1480 285900 300 2220 7401500 300 3705 740

Maximum Operating Pressures to API 526

Size Orifice ANSI Maximum (ins) Flange Pressure

(Psig)Inlet Outlet Inlet Outlet

3x4 L 150 150 285 285300 150 740 285600 150 1240 285600 300 1480 740900 300 2220 7401500 300 2900 7401500 600 3705 1480

4x6 L, M, N 150 150 285 285300 150 740 285600 150 1480 285900 300 2220 7401500 300 3705 740

4x6 P 150 150 285 285300 150 740 285600 150 1305 285600 300 1480 740900 300 2220 7401500 300 3080 7401500 600 3705 1480

6x8 Q 150 150 285 285300 150 740 285600 150 1330 285600 300 1480 740

6x8 R 150 150 285 285300 150 740 285600 150 915 285600 300 1480 740

8x10 T 150 150 285 285300 150 740 285600 150 900 285600 300 1480 740

8x10x10 X 150 150 285 285300 150 740 285

O P E R AT I N G P R E S S U R E S

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(4) Constant, Fb

2/k (k+1)/k2k k-1

Fb =

Pb P

Pb P

-

(k+1)/(k-1)2

k+1k

(5) Mass Flow (imperial units)

High pressure steam correction factor Fn:-Fn = 1.0 when P≤1515 PsiaUse the following formulae when P>1515 Psia(104.5 Bara) and P<3215 Psia (221.7 Bara)

(6) Fn (imperial units)

Liquid Flow

(7) Liquid Flow (imperial units)

Steam Flow (Sonic and Subsonic flow)

A = W 51.5 P Kd Fsh Fb Ff Fn Fp Kc

0.1906 P - 10000.2292 P - 1061

Fn =

A = VL G 38 Kd F1 Fv Kc (P - Pb)

Liquid viscosity correction (Fv):When a relief valve is sized for viscous liquidservice, it should first be sized as it was for non-viscous type application so that a preliminaryrequired discharge area,A, can be obtained.Thenext larger orifice size should be used indetermining the Reynold’s number, R, from eitherof the following relationships:

or

where:

VL = flow rate at the flowing temperature, in U.S.gallons per minute.

G = specific gravity of the liquid at the flowingtemperature referred to water (1.00 at 70ºF).

e = absolute viscosity at the flowingtemperature, in centipoises.

A = effective discharge area, in square inches(from manufacturer’s standard orifice areas).

U = viscosity at the flowing temperature, inSaybolt Universal seconds.

Note:Equation 9 is not recommended forviscosities less than 100 Saybolt Universalseconds. Hence use Fv = 1

After the value of R is determined, thefactor Fv is obtained from graph 1.0.Fv is applied to correct the preliminaryrequired discharge area. If the correctedarea exceeds the chosen standard orificearea, the above calculations should berepeated using the next larger standardorifice size.

R = VL(2800G)e A

(8)

R = 12,700VLu A

(9)

R = Renolds Number

Vis

cosi

ty C

orr

ecti

on

Fac

tor

Fv

Graph 1.0 - capacity correction, Fv, due to viscosity.81

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VA LV E S I Z I N G VA LV E S I Z I N G F O R M U L A E

Overview

A safety valve is fitted to restrict systemoverpressure to a predetermined level; this isnormally 110% of the safety valve set pressure.

In order to ensure that the overpressure is notexceeded, the flow rate through the safety valvehas to be calculated. This calculation uses formulaewhich are derived from ASME VIII and API 520Codes which are recognised throughout the world.

Sizing

The sizing of the safety valve uses data from thephysical properties of the fluid, the valve setpressure, overpressure limits and effectivedischarge area.

Formulae are presented for sizing valves on steam,gas and liquid. The constants used in the sizingformulae may have a different value dependentupon the valve type; where this is the case, it isclearly illustrated on the graph or table. Alldischarge coefficients are relative to the valve typeand have been approved to the ASME VIII Code.

Capacity tables are also shown for sizing on drysaturated steam, air and water. When calculatingthe flow rate through the safety valve, it isimportant that the flow rate through the valve isgreater than the required flow rate generated bythe system.

Selection

The safety valve selected must be suitable for thepressure and temperature required in the system;the appropriate section of the safety valvecatalogue should be referred to.

The selected total discharge area of the safetyvalve must always be greater than the calculateddischarge area required to relieve the system flowrate under all working conditions.

(1) Mass Flow (imperial units)

(2) Volumetric Flow (imperial units)

(3) Constant (C) (imperial units)

Gas and Vapour Flow

A = W TZ C P Kd Fb Ff Fp M Kc

A = Q GTZ 1.175 C P Kd Ff Fb Fp Kc

C = 520 k k+1k-12

k+1

K C C K C CImperial Metric Imperial Metric

1.00 315 2.4 1.38 354 2.691.02 318 2.41 1.40 356 2.701.04 320 2.43 1.42 358 2.721.06 322 2.45 1.44 359 2.731.08 324 2.46 1.46 361 2.741.10 326 2.48 1.48 363 2.761.12 329 2.50 1.50 364 2.771.14 331 2.51 1.52 366 2.781.16 333 2.53 1.54 368 2.791.18 335 2.55 1.56 369 2.801.20 337 2.56 1.58 371 2.821.22 339 2.58 1.60 372 2.831.24 341 2.59 1.62 374 2.841.26 343 2.61 1.64 376 2.851.28 345 2.62 1.66 377 2.861.30 347 2.63 1.68 378 2.871.32 349 2.65 1.70 380 2.891.34 350 2.66 2.00 400 3.041.36 353 2.68 2.20 412 3.13

Nozzle Gas Constant

ASME and API formula are written for imperialunits, we can supply metric equivalent formula ifrequired.

Table 1.0

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B AC K P R E S S U R E A N D B L OW D OW N L I M I T S

Figures shown are expressed as a percentage of set pressure.

Valve type Built up Superimposed Constant Blowdownback variable back superimposed %

pressure % pressure % back pressure %

Conventional spring loaded safety valves

WB 200 10 3 80 10 – 15

WB 400 10 3 80 7

B 10 3 80 10

C 10 3 80 10 – 15D 10 3 80 15 – 20

Balanced bellows spring loaded safety valves

WB 100 50 50 50 10 – 15

WB 300 20 20 20 7

WB 300B 70 70 70 7

D (piston) Gas 70 70 70 15 - 20

D (piston) Liq. 50 50 50 15 - 20

Safeset Pilot operated safety valves

Refer to page 71

O R I F I C E A R E A S

WB Series – Spring Loaded SRVWB100 / 200/ 300 / 300B & 400The actual orifice area is 11% larger than thoseshown in this table. This ensures that afterderating the discharge coefficient in accordancewith industry standards, the full benefits of theAPI 526 orifice area can still be obtained. It isimportant to use the actual coefficient ofdischarge as the areas are already derated.

Safeset – Pilot Operated SRV

The areas shown in the table are actual orificeareas of the main valves and are larger than thestandard API 526 dimensions.This ensures thatafter derating the discharge coefficient inaccordance with industry standards, the fullbenefits of the API 526 orifice area can still beobtained. It is important to use the deratedcoefficient of discharge as the areas are actuals.

Safeflo – Spring Loaded Types

The orifice areas shown in the table are inaccordance with industry standards. API 526does not specify requirements for thermal reliefvalves. It is important to use the deratedcoefficient of discharge as the areas are actuals.

Orifice no. Safefloin2 mm2

1 0.062 402 0.110 713 0.196 1274 0.442 2857 0.169 109

Orifice WB Series Safeset Pilotletter in2 mm2 in2 mm2

D 0.110 71 0.164 106

E 0.196 127 0.256 165

F 0.307 198 0.338 218

G 0.503 325 0.616 397

H 0.785 506 0.871 562

J 1.287 830 1.429 922

K 1.838 1185 2.139 1380

L 2.853 1840 3.167 2043

M 3.600 2320 4.307 2779

N 4.340 2800 5.162 3330

P 6.380 4120 7.068 4560

Q 11.050 7130 12.864 8299

R 16.000 10300 17.758 11456

S – – 22.118 14270

T 26.000 16770 28.860 18619

X – – 44.178 28302

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Symbol Description Imperial Units

A Orifice discharge area sq. ins

C Gas constant, from the specific heat ratio (k);if unknown use a conservative value of 315 (imperial)This can be calculated from equation (3) or Table 1.0 ......dimensionless......

e Liquid absolute viscosity ........Centipoise........Ff Back pressure correction factor for gas - takes account

of subsonic flow Balanced Bellows Valves:WB 300 / 300B: use Graph 2.0, page 87

Fb Back pressure correction factor for gas - takes accountof subsonic flow Conventional Spring Loaded;WB 400;B Series; Pilot Operated Valves;Type A D and E pilots:use Graph 3.0, page 87 or equation (4) ......dimensionless......

Fl Back pressure correction factor for balanced bellowsspring loaded valves (WB 100) liquid duty only,use Graph 4.0, page 88 ......dimensionless......

Fn High temperature steam correction factor.

Fp Subsonic flow factor for low setpressure on gas duty only, use Graph 5.0, page 88 ......dimensionless......

Fsh Correction factor for superheated steamduty only, use Table 4.0 .....dimensionless......

Fv Liquid viscosity correction factor.See page 82 and Graph 1.0 ......dimensionless......

G Specific gravity ......dimensionless......

Kc Derating factor = 0.9 for use withbursting discs; if no bursting disc use 1.0 ......dimensionless......

Kd Certified ASME Code Section VIIIdischarge coefficient to be used for sizing:WB100 / 200 = 0.653 (actual) (actuals are used onWB 300 / 400 = 0.975 (actual) WB valves, as theWB 300B = 0.925 (actual) derating factor hasB Series = 0.857 (derated) been applied to theC Series = 0.509 (derated) the orifice area).D Series (gas) = 0.824 (derated)D Series (liquid) = 0.506 (derated)Pilots:Types A,D,E = 0.849 gases (derated)Pilots:Types B,C = 0.696 liquids (derated)For full bore 8" x 10" x 10" pilot valves refer to page 96 ......dimensionless......

k Isentropic exponent (ratio of specific heats) ......dimensionless......

M Molecular weight ..........kg/kmole..........

P Set pressure + overpressure + atmospheric pressurewhere:- – Overpressure = 10% or 3 Psi whichever is the greater Psia– Atmospheric pressure = 14.7 Psia

Pb Back pressure at safety valve outlet Psia

Q Volumetric flow rate @ standard pressure and temperature (14.7 Psia and 60 ºF) SCFM

R Reynolds number ......dimensionless......

T Temperature at valve inlet deg.R = 460 + ºF deg.Rankine

VL Liquid flow rate us gpm

W Mass flow rate lb/h

w Liquid density lb/cu ft

Z Compressibility factor (when fluid data is unavailable use Z = 1.0) ......dimensionless......

N O M E N C L AT U R E

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Air = 1.0 at 14.7 psia and 60ºF.

Representative data on some vapours and gases useful in sizingsafety relief valves

Gas or Vapour k C C M √M G* √Gimperial metric

Acetaldehyde 1.14 331 2.51 44 6.633 1.519 1.232Acetic Acid 1.15 332 2.52 60 7.746 2.071 1.439Acetylene 1.26 343 2.61 26.04 5.103 0.899 0.948Air 1.40 356 2.70 28.97 5.382 1 1Ammonia 1.31 348 2.64 17.03 4.127 0.587 0.766Argon 1.67 377.5 2.87 40 6.325 1.381 1.175Benzene 1.12 329 2.50 78.11 8.838 2.70 1.643Butadiene 1.3 1.12 329 2.50 54.09 7.355 1.922 1.386n-Butane 1.09 325 2.47 58.12 7.63 2.07 1.439Iso-Butane 1.1 327 2.49 58.12 7.63 2.07 1.439i-Butane 1.11 327 2.49 56.10 7.49 1.937 1.392Iso-Butylene 1.12 329 2.49 56.10 7.49 1.998 1.413Carbon Dioxide 1.29 346 2.68 44.01 6.634 1.53 1.237Carbon Disulphate 1.21 338 2.57 76.13 8.726 2.628 1.621Carbon Monoxide 1.40 356 2.70 28.00 5.292 0.967 0.983Chloride 1.36 353 2.68 70.91 8.421 2.45 1.565Cyclohexane 1.09 325 2.47 84.16 9.174 2.905 1.705Decane 1.03 319 2.42 142 11.92 4.91 2.216Dowthern A 1.043 320 2.43 165 12.85 5.696 2.386Dowthern E — — — 147 12.12 5.074 2.253Ethane 1.19 336 2.55 30.07 5.483 1.05 1.025Ethene (Ethylene) 1.24 341 2.59 28.05 5.297 0.977 0.988Ethyl Alcohol 1.13 330 2.50 46.07 6.787 1.59 1.261Ethyl Benzine 1.07 323 2.46 106.16 10.31 3.67 1.916Ethyl Chloride 1.19 336 2.55 64.50 8.031 2.226 1.492Freon 11 1.14 331 2.51 137.37 11.72 4.742 2.177Freon 12 1.14 331 2.51 120.92 10.995 4.174 2.043Freon 22 1.18 325 2.55 86.48 9.299 2.985 1.727Freon 114 1.09 325 2.47 170.93 13.073 5.90 2.429Helium 1.66 377 2.86 4 2 0.138 0.3716n-Heptane 1.05 321 2.44 100 10 3.49 1.868n-Hexane 1.06 322 2.45 86.17 9.283 2.97 1.723Hydrogen Chloride 1.41 357 2.71 36.47 6.039 1.27 1.127Hydrogen 1.41 357 2.71 2.02 1.421 0.070 0.265Hydrogen Sulphide 1.32 349 2.65 34.08 5.838 1.19 1.091Methane 1.31 348 2.64 16.04 4.005 0.555 0.745Menthyl Alcochol 1.20 337 2.56 32 5.657 1.11 1.054Menthyl Butane 1.08 324 2.46 72.15 8.494 2.49 1.578Methyl Chloride 1.20 337 2.56 50.48 7.105 1.742 1.320Natural Gas 1.27 344 2.61 19 4.359 0.656 0.8099Nitric Oxide 1.40 356 2.70 30 5.477 1.036 1.018Nitrogen 1.40 356 2.70 28.02 5.294 0.967 0.9834Nitrous Oxide 1.30 347 2.63 44 6.633 1.519 1.233Nonane 1.04 320 2.43 128 11.31 4.43 2.105n-Octane 1.05 321 2.44 114.22 10.687 3.94 1.985Oxygen 1.40 356 2.70 32 5.657 1.10 1.0490n-Pentane 1.07 323 2.46 72.15 8.494 2.49 1.578Phenol 1.30 347 2.63 94 9.695 3.27 1.808Propane 1.13 330 2.50 44.09 6.64 1.55 1.245Propylene 1.15 332 2.52 42.08 6.487 1.476 1.214Sulphur Dioxide 1.29 346 2.63 64.06 8.004 2.26 1.503Steam 1.33 349 2.66 18 4.243 0.622 0.7887Styrene 1.07 323 2.46 104.14 10.21 3.60 1.897Toluene 1.09 325 2.47 92 9.592 3.18 1.783

Table 2

Liquid G** G

Acetic Acid 1.05 1.025

Acetone 0.792 0.890

Ammonia 0.617 0.786

Benzene 0.885 0.941

1, 2 Butadiene 0.658 0.811

1, 3 Butadiene 0.627 0.792

Iso-Butane 0.563 0.750

n-Butane 0.584 0.764

j-Butane 0.601 0.775

Carbon Dioxide 0.816 0.903

Carbon Disulphide 1.26 1.122

Chlorine 1.423 1.93

Dowtherm A at 212ºF 0.997 0.999

Dowtherm E at 212ºF 1.181 1.086

Ethane 0.377 0.614

Ethyl Alcohol 0.794 0.891

Ethyl Benene 0.872 0.934

Fuel Oil, Bunker C 1.014 (max.) 1.007

Fuel Oil, No. 3 (60ºF) 0.898 (max.) 0.948

Fuel Oil, No. 5 (60ºF) 0.993 (max.) 0.997

Fuel Oil, No. 6 (60ºF) 0.993 (min.) 0.997

Petrol (Gasoline) 0.75 0.886

Liquid G** G

n-Heptane 0.688 0.830

n-Hexane 0.664 0.815

Hydrochloric Acid (40%) 1.20 1.095

Kerosene 0.82 0.906

Methane 0.248 0.498

Methyl Alcohol (100%) 0.796 0.892

Methyl Butane 0.625 0.791

Naphtha 0.88 0.938

Nitric Acid (91%) 1.50 1.225

Nitrogen 0.804 0.897

Iso-Octane 0.696 0.834

n-Octane 0.707 0.841

Oils, Minerals andLubricants 0.910 0.954

Iso-Pentane 0.625 0.791

n-Pentane 0.631 0.794

Phosphoric Acid 1.88 1.371

Propane 0.508 0.713

Polythene 0.522 0.723

Styrene 0.911 0.955

Sulphuric Acid (87%) 1.80 1.342

Water 1.00 1.00

**Water = 1.0 at 70ºF.

Representative data on liquids useful in sizing safety valves

Table 3

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Example :-Set Pressure = 150 PsigBack Pressure = 45 PsigThe back pressureratio = 45 x 100 = 30% 150

and F1 = 0.88

% Back Pressure = x 100Back Pressure (Psig)Set Pressure (Psig)

Co

rrec

tio

n F

acto

r F

1

Set Pressure (Psig)

Co

rrec

tio

n F

acto

r F

p

Graph 4.0Factor Fl – For application sizing and capacity determination of balanced bellows safetyrelief valves against variable or constant back pressure – liquids only (10% overpressure).

Graph 5.0Factor Fp – For low set pressure – vapours and gases only.

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Co

rrec

tio

n F

acto

r F

f

% Back Pressure =Back Pressure (Psig)Set Pressure (Psig)

x 100

% Back Pressure = x 100Back Pressure (Psia) Set Pressure + Overpressure (Psia)

Bac

k P

ress

ure

Co

rrec

tio

n F

acto

r F

b

Graph 2.0Factor Ff – For application sizing and capacity determination of balanced bellows safetyrelief valves against variable and constant back pressure – vapours and gases only.

Graph 3.0Use the curve to evaluate back pressure correction factor Fb, for pilot valves and forconventional valves with constant back pressure use.

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300 400 500 600 700 800 900 1000 1100 1200

15 250 1.00 0.98 0.93 0.88 0.84 0.80 0.77 0.74 0.72 0.70

20 259 1.00 0.98 0.93 0.88 0.84 0.80 0.77 0.74 0.72 0.70

40 287 1.00 0.99 0.93 0.88 0.84 0.81 0.77 0.74 0.72 0.70

60 308 1.00 0.99 0.93 0.88 0.84 0.81 0.77 0.75 0.72 0.70

80 324 1.00 0.99 0.93 0.88 0.84 0.81 0.77 0.75 0.72 0.70

100 338 1.00 0.99 0.94 0.89 0.84 0.81 0.77 0.75 0.72 0.70

120 350 1.00 0.99 0.94 0.89 0.84 0.81 0.78 0.75 0.72 0.70

140 361 1.00 0.99 0.94 0.89 0.85 0.81 0.78 0.75 0.72 0.70

160 371 1.00 0.99 0.94 0.89 0.85 0.81 0.78 0.75 0.72 0.70

180 380 1.00 0.99 0.94 0.89 0.85 0.81 0.78 0.75 0.72 0.70

200 388 1.00 0.99 0.95 0.89 0.85 0.81 0.78 0.75 0.72 0.70

220 395 1.00 0.99 0.95 0.89 0.85 0.81 0.78 0.75 0.72 0.70

240 403 - 1.00 0.95 0.90 0.85 0.81 0.78 0.75 0.72 0.70

260 409 - 1.00 0.95 0.90 0.85 0.81 0.78 0.75 0.72 0.70

280 416 - 1.00 0.96 0.90 0.85 0.81 0.78 0.75 0.72 0.70

300 422 - 1.00 0.96 0.90 0.85 0.81 0.78 0.75 0.72 0.70

350 436 - 1.00 0.96 0.90 0.86 0.82 0.78 0.75 0.72 0.70

400 448 - 1.00 0.96 0.91 0.86 0.82 0.78 0.75 0.72 0.70

500 470 - 1.00 0.96 0.92 0.86 0.82 0.78 0.75 0.73 0.70

600 489 - 1.00 0.97 0.92 0.87 0.82 0.79 0.75 0.73 0.70

800 520 - - 1.00 0.95 0.88 0.83 0.79 0.76 0.73 0.70

1000 546 - - 1.00 0.96 0.89 0.84 0.78 0.76 0.73 0.71

1250 574 - - 1.00 0.97 0.91 0.85 0.80 0.77 0.74 0.71

1500 597 - - - 1.00 0.93 0.86 0.81 0.77 0.74 0.71

1750 618 - - - 1.00 0.94 0.86 0.81 0.77 0.73 0.70

2000 636 - - - 1.00 0.95 0.86 0.80 0.76 0.72 0.69

2500 670 - - - 1.00 0.95 0.85 0.78 0.73 0.69 0.66

3000 690 - - - - 1.00 0.82 0.74 0.69 0.65 0.62

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Table 4

SetPressurep.s.i.—gauge

SaturatedsteamTemp.°F

Total Steam Temperature in Degrees Fahrenheit

Superheated Steam Correction Factors – FSHFor capacity on superheated steam, multiply saturated steam capacity by correction factor below

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S AT U R AT E D S T E A M C A PAC I T Y C H A RT

Saturated Steam Capacities lb/hr10% over pressure or 3 Psig minimum

WB 400

ORIFICE SIZE LETTER DESIGNATIONSetPsig

D E F G H J K L M N P Q R TGauge

10 142 252 395 648 1011 1658 2367 3675 4637 5590 8217 14232 20607 3348720 208 371 581 952 1486 2436 3479 5401 6815 8216 12077 20918 30288 4921830 263 469 735 1205 1880 3083 4402 6833 8622 10395 15281 26466 38322 6227440 324 578 905 1483 2314 3793 5417 8409 10611 12792 18805 32570 47160 7663450 385 686 1074 1760 2747 4504 6433 9985 12599 15189 22329 38673 55997 9099560 446 794 1244 2038 3181 5215 7448 11561 14588 17586 25853 44776 64834 10535670 506 902 1414 2316 3615 5926 8463 13137 16576 19983 29377 50880 73672 11971780 567 1011 1583 2594 4048 6637 9478 14712 18565 22381 32901 56983 82509 13407790 628 1119 1753 2872 4482 7348 10493 16288 20553 24778 36242 63086 91347 148438

100 689 1227 1922 3150 4915 8059 11509 17864 22541 27175 39948 69190 100184 162799120 810 1444 2261 3705 5782 9480 13539 21016 26518 31969 46996 81396 117859 191521140 932 1660 2601 4261 6650 10902 15569 24167 30495 36763 54044 93603 135534 220242160 1053 1877 2940 4816 7517 12324 17600 27319 34472 41558 61092 105810 153208 248964180 1175 2093 3279 5372 8384 13745 19630 30471 38449 46352 68140 118016 170883 277685200 1296 2310 3618 5928 9251 15167 21661 33622 42426 51146 75185 130223 188558 306407220 1418 2526 3957 6483 10118 16589 23691 36774 46402 55941 82235 142430 206233 335128240 1539 2743 4296 7039 10985 18011 25721 39926 50379 60735 89283 154636 223908 363850260 1661 2959 4635 7595 11853 19432 27752 43077 54356 65529 96331 166843 241582 392571280 1782 3176 4974 8150 12720 20854 29782 46229 58333 70324 103379 179049 259257 421193300 1940 3392 5314 8706 13587 22276 31813 49380 62310 75118 110427 191256 276932 450014320 2025 3609 5653 9262 14454 23697 33843 52532 66287 79912 117474 203463340 2147 3825 5992 9817 15321 25119 35873 55684 70263 84706 124522 215669360 2268 4042 6331 10373 16188 26541 37904 58835 74240 89501 131570 227876380 2390 4258 6670 10929 17056 27963 39934 61987 78217 94295 138618 240083400 2511 4475 7009 11484 17923 29384 41965 65139 82194 99089 145666 252289420 2633 4692 7348 12040 18790 30806 43995 68290 86171 103884 152714 264496440 2755 4908 7688 12596 19657 32228 46025 71442 90148 108678 159761 276703460 2876 5125 8027 13151 20524 33649 48056 74594 94124 113472 166809 288909480 2998 5341 8366 13707 21392 35071 50086 77745 98101 118266 173857 301116500 3119 5558 8705 14263 22259 36493 52116 80897 102078 123061 180905 313323520 3241 5774 9044 14818 23126 37915 54147 84048 106055 127855 187953 325529540 3362 5991 9383 15374 23993 39336 56177 87200 110032 132649 195001 337736560 3484 6207 9722 15930 24860 40758 58208 90352 114008 137444 202048 349943580 3605 6424 10062 16485 25727 42180 60238 93503 117985 142238 209096 362149600 3727 6640 10401 17041 26595 43601 62268 96655 121962 147032 216144 374356620 3848 6857 10740 17596 27462 45023 64299 99807 125939 151826 223192640 3970 7073 11079 18152 28329 46445 66329 102958 129916 156621 230240660 4091 7290 11418 18708 29196 47867 68360 106110 133893 161415 237288680 4213 7506 11757 19263 30063 49288 70390 109262 137869 166209 244335700 4334 7723 12096 19819 30930 50710 72420 112413 141846 171004 251383720 4456 7939 12435 20375 31798 52132 74451 115565 145823 175798 258431740 4577 8156 12775 20930 32665 53553 76481 118716 149800 180592 265479760 4699 8372 13114 21486 33532 54975 78512 121868 153777 185386 272527780 4820 8589 13453 22042 34399 56397 80542 125020 157754 190181 279574800 4942 8805 13792 22597 35266 57819 82572 128171 161730 194975 286622850 5246 9347 14640 23986 37434 61373 87648 136050 171673 206961 304242900 5549 9888 15488 25376 39602 64927 92724 143930 181615 218946 321861950 5853 10429 16336 26765 41770 68482 97800 151809 191557 230932 339481

1000 6157 10970 17183 28154 43938 72036 102876 159688 201499 242918 3571011100 6764 12053 18879 30932 48274 79144 113028 175446 2213831300 7980 14218 22270 36489 56945 93362 133332 2069621500 9155 16313 25551 41863 65334 107114 152972 2374481750 10820 19279 30198 49477 77216 126594 1807932000 12561 22382 35058 57440 89643 146969 2098912250 14403 25664 40199 65863 102788 168520 2406682500 16381 29189 45719 74907 116903 1916622750 18549 33052 51770 84821 132375 2170282900 19976 35593 55751 91344

Note:This chart should be used as a guideline only.

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WAT E R C A PAC I T Y C H A RT



10 10 18 28 45 70 115 164 255 322 388 571 989 1431 232620 13 23 37 60 93 153 219 340 428 516 759 1315 1904 309430 16 28 44 72 112 183 262 407 513 619 909 1575 2281 370640 18 32 51 83 129 212 303 470 593 714 1050 1819 2634 428050 20 36 56 93 144 237 338 525 662 799 1174 2033 2944 478560 22 40 62 101 158 259 371 575 726 875 1286 2228 3225 524170 24 43 67 110 171 280 400 621 784 945 1389 2406 3484 566180 26 46 71 117 183 300 428 664 838 1010 1485 2572 3724 605290 27 48 76 124 194 318 454 704 889 1072 1575 2728 3850 6419

100 29 51 80 131 204 335 478 742 937 1129 1660 2876 4164 6767120 31 56 88 143 224 367 524 813 1026 1237 1819 3150 4561 7412140 34 60 95 155 242 396 566 879 1109 1336 1965 3403 4927 8006160 36 65 101 166 258 424 605 939 1185 1429 2100 3638 5267 8559180 38 68 107 176 274 449 642 996 1257 1515 2228 3858 5587 9078200 40 72 113 185 289 474 676 1050 1325 1597 2348 4067 5889 9569220 42 76 119 194 303 497 709 1101 1390 1675 2463 4265 6176 10036240 44 79 124 203 316 519 741 1150 1451 1750 2572 4455 6451 10483260 46 82 129 211 329 540 771 1197 1511 1821 2677 4637 6714 10911280 48 85 134 219 342 560 800 1242 1568 1890 2778 4812 6968 11323300 50 88 138 227 354 580 829 1286 1623 1956 2876 4981 7212 11720320 51 91 143 234 365 599 856 1328 1676 2020 2970 5144340 53 94 147 241 377 618 882 1369 1728 2083 3062 5303360 54 97 152 248 388 636 908 1409 1778 2143 3150 5456380 56 99 156 255 398 653 932 1447 1826 2202 3237 5606400 57 102 160 262 409 670 957 1485 1874 2259 3321 5752420 59 105 164 268 419 686 980 1522 1920 2315 3403 5894440 60 107 168 275 429 703 1003 1557 1965 2369 3483 6032460 61 109 171 281 438 718 1026 1592 2009 2422 3561 6168480 63 112 175 287 448 734 1048 1627 2053 2475 3638 6301500 64 114 179 293 457 749 1070 1660 2095 2526 3713 6430520 65 116 182 299 466 764 1091 1693 2136 2576 3786 6558540 67 119 186 304 475 778 1112 1725 2177 2625 3858 6683560 68 121 189 310 483 793 1132 1757 2217 2673 3929 6805580 69 123 192 315 492 807 1152 1788 2256 2720 3999 6926600 70 125 196 321 500 820 1172 1819 2295 2767 4067 7044620 71 127 199 326 509 834 1191 1849 2333 2812 4134640 72 129 202 331 517 847 1210 1878 2370 2857 4201660 74 131 205 336 525 860 1229 1908 2407 2902 4266680 75 133 208 341 533 873 1247 1936 2443 2945 4330700 76 135 211 346 541 886 1266 1964 2479 2988 4393720 77 137 214 351 548 899 1284 1992 2514 3031 4455740 78 139 217 356 556 911 1301 2020 2549 3073 4517760 79 141 220 361 563 923 1319 2047 2583 3114 4577780 80 142 223 366 571 935 1336 2074 2617 3154 4637800 81 144 226 370 578 947 1353 2100 2650 3195 4696850 83 149 233 382 596 977 1395 2165 2732 3293 4841900 86 153 240 393 613 1005 1435 2227 2811 3388 4981950 88 157 246 403 630 1032 1474 2289 2888 3481 5118

1000 91 161 253 414 646 1059 1513 2348 2963 3572 52511100 95 169 265 434 678 1111 1586 2463 31071300 103 184 288 472 737 1208 1725 26771500 111 198 309 507 791 1297 1853 28761750 120 213 334 548 855 1401 20012000 128 228 357 585 914 1498 21392250 136 242 379 621 969 15892500 143 255 399 655 1021 16752750 150 267 419 686 10713000 157 279 438 7173250 163 291 455 7463500 169 302 473 7743750 175 312 4894000 181 323 5054250 187 333 5214500 192 342 5364750 197 352 5515000 202 361 5655250 207 3705500 212 3785750 217 3876000 222 395

Water Capacity U.S.G.P.M.10% over pressure or 3 Psig minimum


WB 100/200

9493

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10 50 89 140 229 357 586 836 1298 1638 1975 2903 5028 7280 1183020 74 131 205 336 525 861 1229 1908 2408 2902 4267 7390 10700 1738830 94 167 262 429 670 1098 1568 2434 3071 3703 5443 9427 13650 2218140 115 206 322 528 824 1351 1930 2995 3779 4556 6698 11601 16798 2729650 137 244 383 627 979 1604 2291 3557 4488 5410 7953 13775 19945 3241160 159 283 443 726 1133 1858 2653 4118 5196 6264 9208 15949 23093 3752670 180 321 503 825 1287 2111 3014 4679 5904 7118 10464 18123 26241 4264280 202 360 564 924 1442 2364 3376 5240 6612 7972 11719 20297 29389 4775790 224 399 624 1023 1596 2617 3738 5802 7321 8826 12974 22471 32537 52872

100 245 437 685 1122 1751 2870 4099 6363 8029 9679 14229 24644 35684 57987120 289 514 805 1320 2060 3377 4822 7486 9445 11387 16739 28992 41980 68217140 332 591 926 1518 2369 3883 5546 8608 10862 13095 19250 33340 48275 78448160 375 668 1047 1716 2677 4390 6269 9731 12278 14802 21760 37688 54571 88678180 418 746 1168 1913 2986 4896 6992 10853 13695 16510 24271 42036 60866 98908200 462 823 1289 2111 3295 5402 7715 11976 15111 18218 26781 46384 67162 109138220 505 900 1409 2309 3604 5909 8438 13098 16528 19925 29291 50732 73458 119369240 548 977 1530 2507 3913 6415 9162 14221 17944 21633 31802 55080 79753 129599260 592 1054 1651 2705 4222 6922 9885 15344 19361 23341 34312 59427 86049 139829280 635 1131 1772 2903 4531 7428 10608 16466 20777 25048 36822 63775 92344 150059300 678 1208 1893 3101 4840 7934 11331 17589 22194 26756 39333 68123 98640 160290320 721 1285 2013 3299 5148 8441 12054 18711 23610 28464 41843 72471340 765 1363 2134 3497 5457 8947 12778 19834 25027 30171 44353 76819360 808 1440 2255 3695 5766 9454 13501 20956 26443 31879 46664 81167380 851 1517 2376 3893 6075 9960 14224 22079 27860 33587 49374 85515400 895 1594 2497 4091 6384 10466 14947 23202 29276 35294 51884 89862420 938 1671 2617 4288 6693 10973 15670 24324 30693 37002 54395 94210440 981 1748 2738 4486 7002 11479 16394 25447 32109 38710 56905 98558460 1024 1825 2859 4684 7311 11986 17117 26569 33526 40417 59415 102906480 1068 1902 2980 4882 7619 12492 17840 27692 34942 42125 61926 107254500 1111 1980 3101 5080 7928 12998 18563 28814 36359 43833 64436 111602520 1154 2057 3221 5278 8237 13505 19286 29937 37775 45540 66946 115950540 1198 2134 3342 5476 8546 14011 20010 31060 39192 47248 69457 120297560 1241 2211 3463 5674 8855 14518 20733 32182 40608 48956 71967 124645580 1284 2288 3584 5872 9164 15024 21456 33305 42025 50663 74478 128993600 1327 2365 3705 6070 9473 15530 22179 34427 43441 52371 76988 133341620 1371 2442 3825 6268 9782 16037 22902 35550 44858 54079 79498640 1414 2519 3946 6466 10090 16543 23626 36672 46274 55786 82009660 1457 2597 4067 6663 10399 17050 24349 37795 47691 57494 84519680 1501 2674 4188 6861 10708 17556 25072 38918 49107 59202 97029700 1544 2751 4309 7059 11017 18062 25795 40040 50524 60909 89540720 1587 2828 4429 7257 11326 18569 26518 41163 51940 62617 92050740 1630 2905 4550 7455 11635 19075 27242 42285 53357 64325 94560760 1674 2982 4671 7653 11944 19581 27965 43408 54773 66032 97071780 1717 3059 4792 7851 12253 20088 28688 44530 56190 67740 99581800 1760 3136 4913 8049 12561 20594 29411 45653 57606 69448 102091850 1868 3329 5215 8544 13334 21860 31219 48460 61148 73717 108367900 1977 3522 5517 9038 14106 23126 33027 51266 64689 77986 114643950 2085 3715 5819 9533 14878 24392 34835 54072 68230 82255 120919

1000 2193 3908 6121 10028 15650 25658 36643 56879 71771 86524 1271951100 2409 4293 6724 11018 17195 28190 40259 62492 788541300 2842 5064 7932 12997 20283 33254 47491 737171500 3275 5836 9140 14976 23372 38318 54723 849431750 3816 6800 10650 17450 27233 44648 637632000 4357 7764 12160 19924 31094 50978 728032250 4898 8728 13670 22398 34955 57308 818432500 5439 9692 15180 24872 38816 636382750 5980 10656 16690 27346 42677 699683000 6521 11620 18200 298203250 7062 12584 19710 322943500 7603 13548 21220 347683750 8144 14512 227304000 8685 15476 242404250 9226 16440 257504500 9767 17404 272604750 10308 18368 287705000 10849 19332 302805250 11390 202965500 11931 212605750 12472 222246000 13013 23188

Air Capacity s.c.f.m.10% over pressure or 3 Psig minimum


A I R C A PAC I T Y C H A RT

WB 400

ORIFICE SIZE LETTER DESIGNATION (DISCHARGE AREA sq in)SetPsig D E F G H J K L M N P Q R S TGauge (0.164) (0.256) (0.338) (0.616) (0.871) (1.429) (2.139) (3.166) (4.307) (5.162) (7.068) (12.864) (17.758) (22.118) (28.862)

29 119 186 246 448 634 1039 1556 2303 3133 3755 5141 9357 12917 16088 2099440 150 234 309 563 796 1307 1956 2895 3938 4720 6462 11762 16236 20223 2638760 206 322 425 774 1095 1796 2689 3980 5414 6488 8884 16170 22321 27802 3627680 262 410 541 985 1393 2286 3422 5064 6890 8257 11306 20578 28406 35381 46166

100 319 497 657 1196 1692 2776 4155 6149 8366 10026 13728 24986 34492 42960 56055150 459 717 946 1724 2438 4000 5987 8862 12055 14448 19783 36006 49704 61908 80779200 600 936 1236 2252 3184 5224 7819 11574 15745 18871 25838 47026 64917 80856 105502250 740 1155 1525 2780 3930 6448 9652 14286 19435 23293 31893 58047 80130 99804 130226300 881 1374 1815 3307 4676 7672 11484 16998 23124 27715 37948 69067 95343 118752 154949350 1021 1594 2104 3835 5423 8896 13317 19710 26814 32137 44003 80087 110556 137700 179673400 1162 1813 2394 4363 6169 10121 15149 22423 30504 36559 50058 91107 125768 156647 204397450 1302 2032 2683 4890 6915 11345 16982 25135 34193 40981 56113 102128 140981 175595 229120500 1442 2252 2973 5418 7661 12569 18814 27847 37883 45403 62168 113148 156194 194543 253844550 1583 2471 3263 5946 8407 13793 20646 30559 41573 49826 68223 124168 171407 213491 278567600 1723 2690 3552 6474 9153 15017 22479 33272 45262 54248 74278 135188 186620 232439 303291650 1864 2910 3842 7001 9900 16242 24311 35984 48952 58670 80333 146209 201832 251387 328015700 2004 3129 4131 7529 10646 17466 26144 38696 52642 63092 86388 157229 217045 270335 352738750 2145 3348 4421 8057 11392 18690 27976 41408 56332 67514 92443 168249 232258 289283 377462800 2285 3568 4710 8584 12138 19914 29809 44121 60021 71936 98498 179269 247471 308231 402185850 2426 3787 5000 9112 12884 21138 31641 46833 63711 76358 104553 190290 262684 327179 426909900 2566 4006 5289 9640 13630 22363 33473 49545 67401 80781 110608 201310 277896 346126 451633950 2707 4225 5579 10168 14377 23587 35306 52257 71090 85203 116663 212330 293109 365074 476356

1000 2847 4445 5869 10695 15123 24811 37138 54969 74780 89625 122718 223350 308322 384022 5010801200 3409 5322 7027 12806 18107 29708 44468 65818 89539 107313 146938 267431 369173 459814 5999741400 3971 6199 8185 14917 21092 34604 51798 76667 104298 125002 171157 311512 430024 535605 6988681480 4196 6550 8648 15761 22286 36563 54730 81007 110201 132077 180845 329145 454365 565922 7384261600 4533 7076 9343 17028 24077 39501 59127 87516 119056 142691 195377 355593 4908761800 5095 7954 10501 19139 27061 44398 66457 98365 133815 160379 219597 399674 5517272000 5657 8831 11660 21249 30046 49295 73787 109214 148574 178068 243817 443755 6125782200 6219 9708 12818 23360 33031 54191 81116 120063 163333 195756 268037 487836 6734292400 6781 10585 13976 25471 36015 59088 88446 130912 178091 213445 292257 531917 7342812600 7343 11463 15134 27582 39000 63985 95776 141761 192850 231134 316477 575998 7951322800 7905 12340 16293 29693 41985 68882 103106 152610 207609 248822 340696 620079 8559833000 8467 13217 17451 31804 44969 73778 110435 163459 222368 266511 364916 664160 9168343500 9872 15410 20346 37081 52431 86020 128759 190581 259265 310732 425466 774363 10689623705 10448 16309 21533 39244 55490 91039 136272 201701 274392 328863 450291 819546 11313354000 11277 17603 23242 42358 59892 982624350 12261 19138 25269 46052 65116 1068314500 12682 19796 26137 47635 67354 1105045000 14087 21989 29033 52912 74816 1227465500 15492 24183 31929 58189 82277 1349886000 16897 26376 34824 63466 89739 1472306170 17375 27121 35809 65261 92276 151392

Main Valve Discharge Capacities 10% over pressure or 3 Psig whichever is the greater. Kd = 0.849

Pilot:Types A, D & E

A I R C A PAC I T Y C H A RT - S . C . F. M .

*

*

*

*Note: Type D Pilot is available from 43 to 1480 Psig.Type E Pilot is available from 29 to 4350 Psig.

For 8" x 10" x 10" full bore capacity chart see page 96.

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Actual orifice area Air S.C.F.M. Water U.S.G.P.M.44.178sq.in. @ 60ºF and 10% over pressure @ 10% over pressure

Set pressure Pilot types A, D & E Pilot types B & CPsig Derated kd 0.849 Derated kd 0.696

29 32044 6599

50 47929 8665

100 85749 12254

150 123569 15009

200 161390 17330

250 199210 19376

300 237031 21225

350 274851 22926

400 312671 24509

450 350492 25996

500 388312 27402

550 426132 28739

600 463953 30017

650 501773 31243

700 539593 32422

740 569850 33336

Capacity chart (full bore 8" x 10" x 10" pilot valve)

*Note: Pilot types B and D are available from 43 Psig.

*

D UA L O U T L E T / F U L L B O R E P I L OT VA LV E

This valve is suitable for extremely highcapacity duties. It achieves maximum dischargecapacities by having a full bore 8 inch inletwith an available discharge area of 44.178sq.in. and two opposing 10 inch outlets, whichcan assist with reaction force problems.

Available with all pilot types A, B, C, D and E.

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ORIFICE SIZE LETTER DESIGNATION (DISCHARGE AREA sq in)SetPsig D E F G H J K L M N P Q R S TGauge (0.164) (0.256) (0.338) (0.616) (0.871) (1.429) (2.139) (3.166) (4.307) (5.162) (7.068) (12.864) (17.758) (22.118) (28.862)

29 25 38 51 92 130 214 320 473 644 771 1056 1922 2654 3305 431340 29 45 59 108 153 251 375 555 756 906 1240 2257 3115 3880 506360 35 55 73 132 187 307 460 680 925 1109 1519 2764 3816 4752 620180 41 64 84 153 216 355 531 785 1069 1281 1754 3192 4406 5488 7161

100 45 71 94 171 242 396 593 878 1195 1432 1961 3568 4926 6135 8006150 56 87 115 209 296 485 727 1076 1463 1754 2401 4370 6033 7514 9805200 64 100 133 242 342 561 839 1242 1690 2025 2773 5046 6966 8677 11322250 72 112 148 270 382 627 938 1389 1889 2264 3100 5642 7788 9701 12659300 79 123 162 296 418 687 1028 1521 2069 2480 3396 6181 8532 10627 13867350 85 133 175 320 452 742 1110 1643 2235 2679 3668 6676 9215 11478 14978400 91 142 188 342 483 793 1187 1756 2389 2864 3921 7137 9852 12271 16012450 97 151 199 362 513 841 1259 1863 2534 3037 4159 7570 10449 13015 16983500 102 159 210 382 540 886 1327 1964 2671 3202 4384 7979 11015 13719 17902550 107 167 220 401 567 930 1391 2060 2802 3358 4598 8368 11552 14389 18776600 111 174 230 419 592 971 1453 2151 2926 3507 4802 8741 12066 15028 19611650 116 181 239 436 616 1011 1513 2239 3046 3651 4999 9097 12559 15642 20411700 120 188 248 452 639 1049 1570 2324 3161 3788 5187 9441 13033 16232 21182750 125 194 257 468 662 1086 1625 2405 3272 3921 5369 9772 13490 16802 21925800 129 201 265 483 683 1121 1678 2484 3379 4050 5545 10093 13932 17353 22644850 133 207 273 498 704 1156 1730 2560 3483 4175 5716 10403 14361 17887 23341900 136 213 281 513 725 1189 1780 2635 3584 4296 5882 10705 14778 18406 24018950 140 219 289 527 745 1222 1829 2707 3682 4413 6043 10998 15183 18910 24676

1000 144 225 269 540 764 1253 1876 2777 3778 4528 6200 11284 15577 19401 253171200 158 246 325 592 837 1373 2055 3042 4139 4960 6792 12361 17064 21253 277341400 170 266 351 639 904 1483 2220 3286 4470 5358 7336 13351 18431 22956 299561480 175 273 361 657 929 1525 2283 3379 4596 5509 7543 13728 18950 23603 308001600 182 284 375 683 966 1586 2373 3513 4779 5728 7842 14273 197031800 193 301 398 725 1025 1682 2517 3726 5069 6075 8318 15139 208992000 203 318 419 764 1080 1773 2653 3927 5343 6404 8768 15958 220292200 213 333 440 801 1133 1859 2783 4119 5604 6716 9196 16737 231042400 223 348 459 837 1184 1942 2907 4302 5853 7015 9605 17481 241322600 232 362 478 871 1232 2021 3025 4478 6092 7301 9997 18195 251172800 241 376 496 904 1278 2097 3140 4647 6322 7577 10374 18882 260653000 249 389 514 936 1323 2171 3250 4810 6544 7843 10739 19545 269803500 269 420 555 1011 1429 2345 3510 5196 7068 8471 11599 21111 291423705 277 432 571 1040 1471 2413 3612 5346 7272 8716 11934 21720 299834000 288 449 593 1081 1528 25074350 300 468 618 1127 1593 2614

WAT E R C A PAC I T Y C H A RT - U . S . G . P. M .

Main Valve Discharge Capacities Water u.s.g.p.m.10% over pressure or 3 Psig whichever is the greater. Kd = 0.696

Pilot:Types B & C

*Note: Type B Pilot is available from 43 to 1480 Psig.

For 8" x 10" x 10" full bore capacity chart see page 96.

*

*

98

DE

FIN

ITIO

NS

D E F I N I T I O N O F T E R M S

Pressure Relief Devices

A pressure relief device is actuated by inlet staticpressure and designed to open during an emergencyor abnormal conditions to prevent a rise of internalfluid pressure in excess of a specified value. Thedevice also may be designed to prevent excessiveinternal vacuum. The device may be a pressure reliefvalve, a nonreclosing pressure relief device, or avacuum relief valve.

A spring-loaded pressure relief valve is apressure relief device designed to automaticallyreclose and prevent the further flow of fluid.

A relief valve is a spring-loaded pressure relief valve,actuated by the static pressure upstream of the valve.The valve opens normally in proportion to thepressure increase over the opening pressure. A reliefvalve is used primarily with incompressible fluids.

A safety valve is a spring-loaded pressure reliefvalve, actuated by the static pressure upstream of thevalve and characterised by rapid opening or popaction. A safety valve is normally used withcompressible fluids.

A safety relief valve is a spring-loaded pressurerelief valve that may be used as either a safety orrelief valve, depending on the application.

A conventional pressure relief valve is a spring-loaded pressure relief valve whose performancecharacteristics are directly affected by changes in theback pressure on the valve.

A balanced pressure relief valve is a spring-loadedpressure relief valve that incorporates a means forminimising the effect of back pressure on theperformance characteristics.

A pilot-operated pressure relief valve is apressure relief valve in which the main valve iscombined with and controlled by an auxiliarypressure relief valve.

A rupture disc device is a nonreclosing differentialpressure relief device, actuated by inlet static pressureand designed to function by bursting the pressure-containing rupture disc. A rupture disc deviceincludes a rupture disc and a rupture disc holder.

Dimensional Characteristics of PressureRelief Devices

The actual discharge area is the measuredminimum net area that determines the flowthrough a valve.

The curtain area is the area of the cylindrical orconical discharge opening between the seatingsurfaces above the nozzle seat created by the lift ofthe disc.

The required discharge area, is a nominal orcomputed area of a pressure relief valve used inrecognised flow formulae to determine the size ofthe valve. It will be less than the actual dischargearea.

The nozzle area is the cross-sectional flow areaof a nozzle at the minimum nozzle diameter.

A huddling chamber is an annular pressurechamber in a pressure relief valve located beyondthe seat for the purpose of generating a rapidopening.

The inlet size is the nominal pipe size (NPS) ofthe valve at the inlet connection, unless otherwisedesignated.

The outlet size is the nominal pipe size (NPS) ofthe valve at the discharge connection, unlessotherwise designated.

Lift is the actual travel of the disc away form theclosed position when a valve is relieving.

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The discharge from a safety relief valve exerts areaction force on the valve or outlet piping. If thedischarge piping is unsupported, this force istransmitted to the valve inlet and associated piping.The following formula can be used to determinethe reaction force, assuming that critical flow of thegas or vapour occurs at the valve outlet.

F = Reaction force (lbs).W = Flow rate of gas or vapour (lb/hr).K = Ratio of specific heat (imperial).M = Molecular weight of gas or vapour.T = Temperature at valve inlet, degrees Rankine

(equal to degrees F plus 460).Po = Outlet pressure (psig).Ao = Discharge connection area (in2).

F = W (k+1) M

kT

366+(Po x Ao)

R E AC T I O N F O R C E - VA P O U R S A N D G A S E S

Discharge piping should be adequately supported. Ifpipework is not supported, it must be rememberedthat the reaction force will act on the end of thedischarge pipe, and that the discharge pipe will actas a lever. The force applied to the valve willtherefore be determined by the reaction force andthe geometry of the discharge pipework.

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O P E R AT I O N A L C H A R AC T E R I S T I C S P R E S S U R E T E R M R E L AT I O N S H I P

System Pressures

The maximum operating pressure is themaximum pressure expected during system operation.

The maximum allowable working pressure(MAWP) is the maximum gauge pressure permissiblein a vessel at its designated temperature.Themaximum allowable working pressure is the basis forthe pressure setting of the pressure relief devices thatprotect the vessel.

The design gauge pressure refers to at least themost severe conditions of coincident temperature andpressure expected during operation. This pressuremay be used in place of the maximum allowableworking pressure in all cases where the MAWP hasnot been established.The design pressure is equal toor less than the MAWP.

Accumulation is the pressure increase over themaximum allowable working pressure of the vesselduring discharge through the pressure relief device,expressed in pressure units or as a percentage.Maximum allowable accumulations are established byapplicable codes for operating and fire contingencies.

Overpressure is the pressure increase over the setpressure of the relieving device, expressed in pressureunits or as a percentage. It is the same asaccumulation when the relieving device is set at themaximum allowable working pressure of the vessel.

Rated relieving capacity is that portion of themeasured relieving capacity permitted by the applicablecode or regulation to be used as a basis for theapplication of a pressure relief device.

Stamped capacity is the rated relieving capacity thatappears on the device nameplate. The stampedcapacity is based on the set pressure or burst pressure,plus the allowable overpressure for compressible fluidsand the differential pressure for incompressible fluids.

Device Pressures

The set pressure is the inlet gauge pressure at whichthe pressure relief valve is set to open under serviceconditions.

The cold differential test pressure is the pressureat which the pressure relief valve is adjusted to openon the test stand. The cold differential test pressureincludes corrections for the service conditions of backpressure or temperature or both.

Back Pressure is the pressure that exists at theoutlet of a pressure relief device as a result of the

pressure in the discharge system. It is the sum ofthe superimposed and built-up back pressure.

Built up back pressure is the increase in pressurein the discharge header that develops as a result offlow after the pressure relief device opens.

Superimposed back pressure is the staticpressure that exists at the outlet of a pressure reliefdevice at the time the device is required to operate.It is the result of pressure in the discharge systemcoming from other sources and may be constant orvariable.

Blowdown is the difference between the setpressure and the closing pressure of a pressurerelief valve, expressed as a percent of the setpressure or in pressure units.

Opening pressure is the value of increasing inletstatic pressure at which there is a measurable lift ofthe disc or at which discharge of the fluid becomescontinuous.

Closing pressure is the value of decreasing inletstatic pressure at which the valve disc re-establishescontact with the seat or at which lift becomes zero.

Simmer is the audible or visible escape ofcompressible fluid between the seat and disc at aninlet static pressure above the set pressure and atno measurable capacity.

Leak-test pressure is the specified inlet staticpressure at which a seat leak test is performed(normally 90% of set pressure according toAP1 527).

The term relieving conditions is used to indicatethe inlet pressure and temperature on a pressurerelief device at a specific overpressure. The relievingpressure is equal to the valve set pressure (orrupture disc burst pressure) plus the overpressure.(The temperature of the flowing fluid at relievingconditions may be higher or lower than theoperating temperature.)

Popping pressure is the pressure at which thevalve disc rapidly moves from a slightly open(simmer) position to a practically full open position.

Discharge capacity is the actual mass flow rate ofdischarge which can also be expressed in volumetricterms.

Equivalent capacity is the mass volumetric flowrate of a fluid calculated from the capacity of thevalve for a test fluid.The fluids commonly used forthe test purposes are steam, air and water.

Pressure VesselRequirements

Vessel Pressure% Design Pressure

Safety ValveCharacteristic

Maximum relieving pressure

110

100

90

Notes: The system operating pressure must not exceed the reseat pressure of the safety valve.Blowdown control is designed to conform to ASME Code Section V111, however liquidapplications may demand up to 15% blowdown.

Overpressure and blowdowns shown are typical for spring loaded SRVs and can bereduced when using Safeset Pilot Operated SRVs. Refer to the appropriate cataloguesection for details.

Accumulation

Blowdown (Typical)

Operating margin

Overpressure (Typical)

Maximum permitedaccumulated pressure

Design pressure Set pressure

Reseat pressure

Maximum operatingpressure

Documents

Safety Relief Valves